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Disclosures: Steven R Feldman, MD, PhD Grant/Research/Clinical Trial Support: Amgen [psoriasis (etanercept, brodalumab)]; Abbvie [psoriasis (adalimumab)]; Janssen [psoriasis (ustekinumab)]; Novartis [psoriasis (secukinumab)]; Pfizer [psoriasis (tofacitinib)]; Celgene [psoriasis (apremilast)]; Galderma [psoriasis (Clobetasol)]. Speaker's Bureau: Janssen [psoriasis (ustekinumab)]; Galderma [psoriasis (Clobetasol)]. Consultant/Advisory Boards: Amgen [psoriasis (etanercept, brodalumab)]; Abbvie [psoriasis (adalimumab)]; Novartis [psoriasis (secukinumab)]; Pfizer [psoriasis (tofacitinib)]; Celgene [psoriasis (apremilast)]; Galderma [psoriasis (Clobetasol)]; Lilly [psoriasis (ixekizumab)]. Robert P Dellavalle, MD, PhD, MSPH Nothing to disclose. Kristina Callis Duffin, MD Grant/Research/Clinical Trial Support: Amgen [Psoriasis (Etanercept, brodalumab)]; Pfizer [Psoriasis (Tofacitinib)]; Bristol-Myers Squibb [Psoriasis (Abatacept)]; Eli Lilly and Company [Psoriasis (Ixekizumab, baricitinib)]; AbbVie [Psoriasis (Adalimumab)]; Janssen [Psoriasis (Ustekinumab, guselkumab). Consultant/Advisory Boards: Amgen [Psoriasis (Etanercept, brodalumab)]; Pfizer [Psoriasis (Tofacitinib)]; Bristol-Myers Squibb [Psoriasis (Abatacept)]; Eli Lilly and Company [Psoriasis (Ixekizumab, baricitinib)]; Janssen [Psoriasis (Ustekinumab, guselkumab). Abena O Ofori, MD Employee of UpToDate, Inc.

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Literature review current through: Jul 2014. | This topic last updated: Jul 11, 2014.

INTRODUCTION — Psoriasis is a common chronic skin disorder typically characterized by erythematous papules and plaques with a silver scale, although other presentations occur. Most cases are not severe enough to affect general health and are treated in the outpatient setting. Rare life-threatening presentations can occur that require intensive inpatient management.

This topic reviews the treatment of psoriatic skin disease. The epidemiology, clinical manifestations, and diagnosis of psoriatic skin disease are discussed in detail separately, as are psoriatic arthritis and the management of psoriasis in pregnant women and special populations. (See "Epidemiology, clinical manifestations, and diagnosis of psoriasis" and "Treatment of psoriatic arthritis" and "Pathogenesis of psoriatic arthritis" and "Clinical manifestations and diagnosis of psoriatic arthritis" and "Management of psoriasis in pregnant women" and "Treatment selection for moderate to severe plaque psoriasis in special populations".)

APPROACH

General — Numerous topical and systemic therapies are available for the treatment of psoriasis. Treatment modalities are chosen on the basis of disease severity, relevant comorbidities, patient preference (including cost and convenience), efficacy, and evaluation of individual patient response [1].

Because of the relatively poor adherence to treatment regimens frequently seen with topical therapies, patient preference is a key aspect of decision making. Additionally, patients are typically started on safer therapies and then progress to more aggressive therapies if the response is inadequate. Clinicians need to carefully review the risk-benefit profiles of proposed therapies.

Psychosocial aspects — Psoriasis can be a frustrating disease for the patient and the provider. The clinician needs to be empathetic and spend adequate time with the patient. It may be helpful for the clinician to touch the patient when appropriate to communicate physically that the skin disorder is neither repulsive nor contagious.

Clinicians should lay out reasonable aims of treatment, making it clear to the patient that the primary goal of treatment is control of the disease rather than cure.

Educating the patient about psoriasis is important and referral to an organization such as the National Psoriasis Foundation (www.psoriasis.org) is often helpful.

Psoriasis may affect patients' perceptions of themselves and this can potentially initiate or exacerbate psychological disorders such as depression [2,3]. Patients with limited skin disease may still have significant psychosocial disability [4]. Some patients with psoriasis may benefit from counseling and/or treatment with psychoactive medications.

Choice of therapy — For most patients, the initial decision point around therapy will be between topical and systemic therapy. However, even patients on systemic therapy will likely continue to need some topical agents. Topical therapy may provide symptomatic relief, minimize required doses of systemic medications, and may even be psychologically cathartic for some patients.

For purposes of treatment planning, patients may be grouped into mild-to-moderate and moderate-to-severe disease categories. Limited, or mild-to-moderate, skin disease can often be managed with topical agents, while patients with moderate-to-severe disease may need systemic therapy. The location of the disease and the presence of psoriatic arthritis also affect the choice of therapy. Psoriasis of the hand, foot, or face can be debilitating functionally or socially and may deserve a more aggressive treatment approach. The treatment of psoriatic arthritis is discussed separately. (See "Treatment of psoriatic arthritis".)

Moderate-to-severe psoriasis is typically defined as involvement of more than 5 to 10 percent of the body surface area (the entire palmar surface, including fingers, of one hand is approximately 1 percent of the body surface area [5]) or involvement of the face, palm or sole, or disease that is otherwise disabling. Patients with more than 5 to 10 percent body surface area affected are generally candidates for systemic therapy, since application of topical agents to a large area is not usually practical or acceptable for most patients. Attempts to treat extensive disease with topical agents are often met with failure, can add cost, and lead to frustration in the patient-clinician relationship.

There is ample evidence of efficacy of the newer systemic therapies ("biologics"); however, cost is a major consideration with these agents. Established therapies such as methotrexate and phototherapy continue to play a role in the management of moderate to severe plaque psoriasis. The management of patients with extensive or recalcitrant disease is a challenge even for experienced dermatologists.

The concept that many patients with psoriasis in the United States do not receive sufficient treatment to control the disease is suggested by an analysis of surveys performed by the National Psoriasis Foundation between 2003 and 2011 [6]. Among the 5604 survey respondents with psoriasis, 52 percent expressed dissatisfaction with their treatment. Many patients received no treatment, including 37 to 49 percent of respondents with mild psoriasis, 24 to 36 percent of respondents with moderate psoriasis, and 9 to 30 percent of respondents with severe psoriasis. Further studies will be useful for clarifying the reasons for these observations and for determining the value of interventions to increase the accessibility of treatment.

Widespread pustular disease requires aggressive treatment, which may include hospitalization. Therapeutic approaches to generalized pustular psoriasis and psoriatic arthritis are discussed separately. (See "Pustular psoriasis: Management" and "Treatment of psoriatic arthritis".)

Mild-to-moderate disease — Limited plaque psoriasis responds well to topical corticosteroids and emollients. Alternatives include tar, topical retinoids (tazarotene), and vitamin D analogs including calcipotriene and calcitriol. For facial or intertriginous areas, topical tacrolimus or pimecrolimus may be used as alternatives or as corticosteroid sparing agents, though improvement may not be as rapid. Localized phototherapy is another option for recalcitrant disease.

Combinations of potent topical corticosteroids (table 1) and either calcipotriene, calcitriol, tazarotene, or UVB phototherapy are commonly prescribed by dermatologists. Calcipotriene in combination with Class I topical corticosteroids is highly effective for short-term control. Calcipotriene alone can then be used continuously and the combination with potent corticosteroids used intermittently (on weekends) for maintenance. A combination product containing calcipotriene and betamethasone dipropionate is available for this use. With proper adherence, considerable improvement with topical therapies may be seen in as little as one week, though several weeks may be required to demonstrate full benefits.

Severe disease — Severe psoriasis requires phototherapy or systemic therapies such as retinoids, methotrexate, cyclosporine, or biologic immune modifying agents. Biologic agents used in the treatment of psoriasis include the anti-TNF agents adalimumab, etanercept, and infliximab and the anti-IL-12/23 antibody ustekinumab. Improvement usually occurs within weeks. Patients with severe psoriasis generally require care by a dermatologist.

Intertriginous psoriasis — Intertriginous (inverse) psoriasis should be treated with class VI and VII low potency corticosteroids (table 1) due to an increased risk of corticosteroid-induced cutaneous atrophy in the intertriginous areas. Topical calcipotriene or calcitriol and the topical calcineurin inhibitors tacrolimus or pimecrolimus are additional first-line treatments [7,8]. These agents may be used alone or in combination with topical corticosteroids as corticosteroid sparing agents for long term maintenance therapy. Calcipotriene, tacrolimus, and pimecrolimus are more expensive options than topical corticosteroids. Some concerns have been raised about the safety of the calcineurin inhibitors. (See "Epidemiology, clinical manifestations, and diagnosis of psoriasis", section on 'Inverse psoriasis' and 'Calcineurin inhibitors' below.)

Scalp psoriasis — The presence of hair on the scalp can make topical treatment of psoriasis challenging because patients may find certain products messy or difficult to apply. Recognizing the patient’s preference for a drug vehicle may help to improve adherence to therapy. For many patients, lotion, solution, gel, foam, or spray vehicles are preferable to thicker creams or ointments.

Topical corticosteroids are the primary topical agents used for psoriasis on the scalp [9]. Support for the use of these agents is evident in a systematic review of randomized trials that found that very potent or potent topical corticosteroids are more effective treatments for scalp psoriasis than topical vitamin D analogs [10]. Combining a corticosteroid and vitamin D analog may offer additional benefit; in the systematic review, combination treatment with a potent topical corticosteroid and a vitamin D analog appeared slightly more effective than potent topical corticosteroid monotherapy. However, in clinical practice, complicating the treatment regimen with more than one topical product may reduce the likelihood of consistent adherence to the treatment regimen. Thus, we usually prescribe a topical corticosteroid alone as initial therapy. A commercially available betamethasone dipropionate-calcipotriene combination product is available, but is more expensive than most topical corticosteroid preparations.

Other topical therapies used for psoriasis (eg, tazarotene, coal tar shampoo, anthralin) and intralesional corticosteroid injections also may be beneficial for scalp involvement, though data on efficacy specifically in scalp disease are limited [9]. Salicylic acid can be a helpful adjunctive treatment because of its keratolytic effect. Phototherapy (eg, excimer laser) and systemic agents are additional treatment options for patients who cannot achieve sufficient improvement with topical agents [9].

Guttate psoriasis — The management of guttate psoriasis is reviewed separately. (See "Guttate psoriasis", section on 'Treatment'.)

Generalized pustular psoriasis — The management of generalized pustular psoriasis is reviewed separately. (See "Pustular psoriasis: Management".)

Localized pustular psoriasis — Localized pustular psoriasis (palms and soles) is difficult to treat. Approaches include potent topical corticosteroids and topical bath PUVA. Data are limited on the use of systemic retinoids for localized pustular psoriasis. However, these drugs appear to be particularly effective in the treatment of pustular psoriasis, and we consider them first line therapy. Acitretin is the retinoid that is used most often for this indication.

Nail psoriasis — Although nail involvement alone is uncommon, many patients with psoriasis have disease that involves the nails. Psoriasis pathology resides in the nail matrix, nail bed, and hyponychium. (See "Epidemiology, clinical manifestations, and diagnosis of psoriasis", section on 'Nail psoriasis'.)

Physical maneuvers to improve nail appearance or comfort may be helpful for some patients. Patients can thin their nails by scraping them with a file or shaving them down with the edge of a glass slide. Thick toenails that are painful or interfere with footwear can be removed by a podiatrist.

Despite advances in the treatment of cutaneous disease, the treatment of psoriasis of the nails remains difficult. There is relatively little evidence to guide the choice of therapies for nail disease [11].

Topical therapies are sometimes tried; however, delivering topical treatment is difficult because of the physical barrier of the nail plate. If improvement in nail appearance occurs, it can be expected to be slow, as 8 to 12 months are needed to generate a new, healthy nail.

There is no standardized regimen for the treatment of nail psoriasis with topical agents [11]. For distal nail onycholysis (separation of the nail from the nail bed), we suggest starting with a class I or II topical corticosteroid (table 1), such as clobetasol 0.05% solution, combined with calcipotriene 0.005% solution dripped into the nail bed and hyponychium twice daily. For patients with nail pitting and other superficial nail defects, the pathologic process is occurring under the proximal nail fold. We typically use a high potency topical corticosteroid (class I or II) and a topical vitamin D analog applied once or twice daily under an occlusive dressing. The use of a combination product containing both a corticosteroid and a vitamin D analog may simplify treatment [12]. Cutaneous atrophy is a potential adverse effect of the long-term use of potent topical corticosteroids.

For severe or recalcitrant nail disease, intralesional therapy with corticosteroids is a reasonable next option.

Systemic therapy may be more effective than topical therapy. A randomized trial of infliximab in patients with moderate to severe psoriasis (82 percent of whom had nail psoriasis) found marked improvements in nail pathology compared with baseline and with placebo [13]. Treatment with other biologic agents, including adalimumab, etanercept, ustekinumab, and golimumab have also led to improvement in nail psoriasis [14-18].

Oral retinoids have been utilized in the treatment of nail psoriasis with some success. A study of low-dose acitretin (0.2-0.3 mg/kg) given to 36 patients with isolated nail psoriasis for six months led to complete or almost complete clearance in 25 percent, moderate improvement in 25 percent, mild improvement in 33 percent, and no improvement in 11 percent [19]. At a six month follow-up visit after the end of treatment, recurrence of nail psoriasis was noted. However, patients who improved with acitretin had less severe nail findings than at the start of treatment. (See 'Retinoids' below.)

Photochemotherapy (PUVA) and pulsed dye laser therapy [20] have also been used for the treatment of nail psoriasis. Evidence for the efficacy of PUVA is limited to reports from small, uncontrolled studies [21,22].

In choosing among treatments, serious consideration must be given to the risks of systemic therapy and photochemotherapy.

Erythrodermic psoriasis — There is no high quality evidence to support specific recommendations for the management of erythrodermic psoriasis. Based upon data from open-label or retrospective studies and case reports, a panel of experts suggested that patients with severe, unstable disease should be treated with cyclosporine or infliximab due to the rapid onset and high efficacy of these agents [23]. Patients with less acute disease can be treated with acitretin or methotrexate as first-line agents. The panel advised against the use of systemic glucocorticoids due to the potential for these drugs to induce a flare of psoriasis upon withdrawal of therapy. (See 'Systemic therapies' below.)

Data are limited on the efficacy of biologic agents other than infliximab for the treatment of erythrodermic psoriasis. Etanercept was effective in an open-label study of 10 patients [24], and case reports have documented successful treatment with adalimumab and ustekinumab [25,26].

In general, patients with erythrodermic psoriasis should be cared for by a dermatologist and may require hospitalization and/or combinations of systemic treatments. Topical therapies, such as mid-potency topical corticosteroids, emollients, wet dressings, and oatmeal baths can be used in concordance with systemic treatment to manage symptoms [23]. Long-term maintenance therapy for psoriasis is required.

Children — The immediate and long-term adverse effects of therapies for psoriasis are of particular concern in the pediatric population. Many agents used in the treatment of adult psoriasis have also been used for children. However, high quality studies on the efficacy and safety of therapies for psoriasis in children are limited. Guidelines for the treatment of children based upon the available evidence have been published [27].

Special populations — The treatment of psoriasis in pregnant women and patients with hepatitis B, hepatitis C, human immunodeficiency virus infection, latent tuberculosis, or malignancy is reviewed separately. (See "Treatment selection for moderate to severe plaque psoriasis in special populations" and "Management of psoriasis in pregnant women".)

Referral — Referral to a dermatologist should be considered in the following settings:

Confirmation of the diagnosis is needed.

The response to treatment is inadequate as measured by the clinician, patient, or both.

There is significant impact on quality of life.

The primary care clinician is not familiar with the treatment modality recommended such as PUVA, phototherapy, or immunosuppressive medications.

The patient has widespread severe disease.

In cases of psoriatic arthritis, referral and/or collaboration with a rheumatologist is indicated. (See "Treatment of psoriatic arthritis".)

TOPICAL THERAPIES — Patient adherence may be the largest barrier to treatment success with topical therapies; frequent patient follow-up (initially every week) may improve adherence. Published guidelines for the treatment of psoriasis with topical therapies are available [28].

Emollients — Hydration and emollients are valuable and inexpensive adjuncts to psoriasis treatment. Keeping psoriatic skin soft and moist minimizes the symptoms of itching and tenderness. Additionally, maintaining proper skin hydration can help prevent irritation and thus the potential for subsequent Koebnerization (development of new psoriatic lesions at sites of trauma).

The most effective are ointments such as petroleum jelly or thick creams, especially when applied immediately after a hydrating bath or shower.

Corticosteroids — Topical corticosteroids remain the mainstay of topical psoriasis treatment despite the development of newer agents [29]. The mechanism of action of corticosteroids in psoriasis is not fully understood. Corticosteroids exert antiinflammatory, antiproliferative, and immunosuppressive actions by affecting gene transcription.

The inherent potency of a topical corticosteroid is frequently reported using a I to VII scale based on vasoconstrictive assays (table 1). Although ointments are sometimes thought to be inherently more effective because of their occlusive properties, this is not uniformly correct. In practice, the efficacy/potency of a topical corticosteroid is dependent on many factors including skin type, plaque thickness, and, perhaps most importantly, compliance.

To minimize adverse effects and maximize compliance, the site of application needs to be considered in choosing the appropriately potent corticosteroid:

On the scalp or in the external ear canal, potent corticosteroids in a solution or foam vehicle (eg, fluocinonide 0.05% or clobetasol propionate 0.05%) are frequently indicated. Clobetasol 0.05% shampoo or spray can also be used for scalp involvement.

On the face and intertriginous areas, a low potency cream (eg, hydrocortisone 1%) is often sufficient.

For thick plaques on extensor surfaces, potent preparations (eg, betamethasone 0.05% or clobetasol propionate 0.05%) are often required.

The typical regimen consists of twice daily application of topical corticosteroids. Most patients will show a rapid decrease in inflammation with such therapy, but complete normalization of skin or lasting remission is unpredictable.

Topical corticosteroids generally can be continued as long as the patient has thick active lesions. Skin atrophy from topical corticosteroids usually is not a problem unless the medication is continuously applied after the skin has returned to normal thickness. Once clinical improvement occurs, the frequency of application should be reduced [28]. For patients in whom lesions recur quickly, topical corticosteroids can be applied intermittently (such as on weekends only) to maintain improvement. The addition of non-corticosteroid treatments can also facilitate the avoidance of long-term daily topical corticosteroids. (See 'Mild-to-moderate disease' above.)

The risks of cutaneous and systemic side effects associated with chronic topical corticosteroid use are increased with high potency formulations. Current data support limiting the continuous application of Class I topical corticosteroids to two to four weeks; thus, close clinician supervision should be employed if longer treatment durations are required (table 1) [28]. Data are less clear regarding treatment durations for less potent topical corticosteroids. Side effects of topical corticosteroids, including the potential for suppression of the hypothalamic axis, are discussed separately. (See "Pharmacologic use of glucocorticoids" and "General principles of dermatologic therapy and topical corticosteroid use".)

The cost of topical corticosteroids varies widely. The price of a 60 gram tube of a potent corticosteroid brand name product can be as high as $80 or more. There are now generic preparations in each potency class that have reduced the cost somewhat. Examples of available generics include, in order of increasing potency, hydrocortisone 1%, triamcinolone 0.1%, fluocinonide 0.05%, betamethasone dipropionate 0.05%, and clobetasol 0.05%.

Different formulations have been developed in an effort to enhance the delivery of topical corticosteroids. Betamethasone valerate in a foam was found to have superior efficacy for scalp psoriasis and was preferred by patients when compared with betamethasone valerate lotion [30]. The foam becomes a liquid on contact with skin and is also well tolerated by patients with trunk and extremity psoriasis [31]. A clobetasol propionate spray is also available; like foams, sprays are easy to apply to large areas [32]. The main advantage of these newer preparations is likely greater patient acceptance, which may translate into greater adherence; the main disadvantage is cost.

Topical vitamin D analogs — Topical vitamin D analogs for the treatment of psoriasis include calcipotriene (calcipotriol), calcitriol, and tacalcitol. Although topical vitamin D analogs are effective as monotherapy for some patients, a systematic review found that combination therapy with a topical corticosteroid is more effective than either treatment alone [33].

Until 2009, calcipotriene was the only topical vitamin D analog available in the United States. Calcipotriene is obtainable as a cream, solution, ointment, or foam, or as a combination ointment or suspension with betamethasone dipropionate. Topical calcitriol ointment has been prescribed in Europe for years, and is now available in the United States. When compared with calcipotriene, calcitriol appears to induce less irritation in sensitive areas of the skin (eg, skin folds) [34].

Calcipotriene — Calcipotriene (calcipotriol) is an established therapy in psoriasis. The precise mechanism is not clear, but a major effect is the hypoproliferative effect on keratinocytes [35]. An immune modulating effect has been postulated for calcipotriene, but has not been shown to be significant in psoriasis to date [36].

In a systematic review of randomized controlled trials, calcipotriene was at least as effective as potent topical corticosteroids, calcitriol, short contact dithranol, tacalcitol, coal tar and combined coal tar 5%, allantoin 2%, and hydrocortisone 0.5% [37]. Only potent topical corticosteroids appeared to have comparable efficacy at eight weeks. Skin irritation is the main adverse event associated with calcipotriene.

Combined use of calcipotriene and superpotent corticosteroids has demonstrated increased clinical response and tolerance in clinical trials compared with either agent used alone [38-40]. One regimen employed daily use of both calcipotriene ointment and halobetasol ointment for two weeks, followed by weekend use of the halobetasol ointment and weekday use of calcipotriene [38]. This regimen produced six-month remission maintenance in 76 percent compared with 40 percent with weekend halobetasol alone. A similar regimen with calcipotriene ointment and clobetasol propionate foam also appears to be effective [41].

In addition, a randomized trial found that a preparation that combines calcipotriene with betamethasone dipropionate (0.064%) was effective with once daily usage, and more effective than once daily therapy with either betamethasone or calcipotriene [42]; this combination preparation typically costs more than $400 for a 60 g tube. Patients who use topical corticosteroids in combination with calcipotriene must be monitored for adverse effects as with corticosteroid monotherapy. (See 'Corticosteroids' above.)

Thus, topical calcipotriene may be used as an alternative or adjunct to topical corticosteroid therapy. It is applied twice daily when used as monotherapy. No controlled trials guide how best to use topical corticosteroids in conjunction with calcipotriene. Once daily use of each may be adequate. Acidic products can inactivate topical calcipotriene, and some topical corticosteroids may be acidic. A reasonable approach to combination therapy is to have patients apply topical calcipotriene and topical corticosteroids each once daily at different times of day.

Other than skin irritation, side effects of topical calcipotriene are usually minimal; the risk of hypercalcemia is low when the drug is used appropriately [43]. However, topical calcipotriene is more expensive than most potent corticosteroids (approximately $300 in the United States for 100 grams).

Calcitriol — The mechanism of action of calcitriol is thought to be similar to that of calcipotriene and involves the drug's ability to inhibit keratinocyte proliferation and stimulate keratinocyte differentiation [44]. In addition, it has been demonstrated that calcitriol inhibits T cell proliferation and other inflammatory mediators [44]. In two randomized trials with a total of 839 patients with mild to moderate plaque psoriasis, calcitriol 3 mcg/g ointment was more effective than vehicle [45]. At the end of the study periods (up to eight weeks), 39.6 and 32.7 percent of the calcitriol groups versus 21.2 and 12 percent of the vehicle groups exhibited at least marked global improvement.

In a systematic review, calcipotriene and calcitriol were equally effective [33]. However, on sensitive areas of the skin, calcitriol appears to be less irritating than calcipotriene. An intraindividual randomized trial of 75 patients compared treatment with calcitriol 3 mcg/g ointment to calcipotriene 50 mcg/g ointment for mild to moderate psoriasis on facial, hairline, retroauricular, and flexural areas [34]. Perilesional erythema, perilesional edema, and stinging or burning sensations were significantly lower in the areas treated with calcitriol. A 52-week open-label study of the safety of calcitriol ointment did not reveal an adverse effect on calcium homeostasis [46].

Calcitriol ointment is expensive; the cost of a 100 gram tube is approximately $400. The drug is applied twice daily.

Tar — The use of tar is a time-honored modality for treating psoriasis, although newer (and less messy) treatment options have reduced its popularity. The precise mechanism of action of tar is not known; it has an apparent antiproliferative effect.

Tar can be helpful as an adjunct to topical corticosteroids. There are no commercially available corticosteroid/tar combinations. Tar products are available without a prescription in the form of shampoos, creams, lotions, ointments, and oils. Newer products include a solution and a foam. Some patients may prefer the less messy new formulations.

Tar can also be compounded into creams and ointments. A commonly used compound is 2% or 3% crude coal tar in triamcinolone cream 0.1% applied twice daily to individual plaques. An alternative is 4 to 10% LCD (liquor carbonis detergens, a tar distillate) in triamcinolone cream or ointment, used similarly. A preparation of 1% tar in a fatty-acid based lotion may be superior to conventional 5% tar products [47] and appears to have efficacy similar to that of calcipotriene [48].

Topical tar preparations, including shampoos, creams, and other preparations, can be used once daily. Patients should be warned that tar products have the potential to stain hair, skin, and clothing. It may help to use them at night and wear inexpensive night clothes (eg, old pajamas) as they tend to be messy. Patients may also find the odor of tar products unpleasant.

For shampoos, the emphasis should be on making sure the product reaches the scalp. Tar shampoo should be left in place for 5 to 10 minutes before rinsing it out.

Tazarotene — Tazarotene is a topical retinoid that was found to be safe and effective in two randomized, vehicle-controlled trials that included 1303 patients with psoriasis [49]. The 0.1% cream was somewhat more effective than 0.05% cream, but with a slightly higher rate of local side effects. Another study found that once daily administration of tazarotene gel, 0.05% or 0.1%, compared favorably with the twice daily administration of topical fluocinonide 0.05% [50]. Absorption of tazarotene was minimal over the 12-week course of the study, suggesting that systemic toxicity is unlikely during long-term therapy. A small uncontrolled study of short contact tazarotene found that a 20 minute application followed by washing appeared to be less irritating than traditional use, and seemed to have similar efficacy [51].

Calcineurin inhibitors — Topical tacrolimus 0.1% and pimecrolimus 1% are effective in the treatment of psoriasis [52-55]. Facial and intertriginous areas may be suited to these treatments, which can allow patients to avoid chronic topical corticosteroid use:

An eight-week randomized trial in 167 patients ages 16 and older found that twice daily treatment to intertriginous and facial lesions with tacrolimus 0.1% ointment resulted in more patients achieving clearance of lesions or excellent improvement compared with placebo (65 versus 32 percent) [56].

An eight-week randomized trial in 57 adults with moderate to severe inverse psoriasis found that twice daily treatment with pimecrolimus 1% cream resulted in more patients clearing or almost clearing lesions compared with placebo (71 versus 21 percent) [57].

Topical tacrolimus and pimecrolimus are generally well-tolerated when used to treat facial and intertriginous psoriasis [56,57]. However, corticosteroid therapy may be more effective, at least compared with pimecrolimus. This was suggested in a four-week randomized trial in 80 patients with intertriginous psoriasis that compared various therapies applied once daily [58]. Betamethasone valerate 0.1% was more effective than pimecrolimus 1%.

In 2005, the US Food and Drug Administration (FDA) issued an alert about a possible link between topical tacrolimus and pimecrolimus and cases of lymphoma and skin cancer in children and adults [59], and in 2006 placed a "black box" warning on the prescribing information for these medications [60]. No definite causal relationship has been established; however, the FDA recommended that these agents only be used as second line agents for atopic dermatitis. If these drugs are used for the treatment of psoriasis, it would be reasonable to follow the additional safety recommendations made by the FDA for their use in atopic dermatitis. (See "Treatment of atopic dermatitis (eczema)", section on 'Topical calcineurin inhibitors'.)

Anthralin — Topical anthralin (also known as dithranol) is an effective treatment for psoriasis that has been utilized since the early 20th century [61-63]. The mechanism of action of anthralin in psoriasis is not well understood, but may involve antiinflammatory effects and normalization of keratinocyte differentiation [28].

Skin irritation is an expected side effect of anthralin that can limit the use of this therapy. This side effect and the ability of anthralin to cause permanent red-brown stains on clothing and temporary staining of skin have contributed to a decline in the use of anthralin therapy.

In order to minimize irritation, anthralin treatment is usually prescribed as a short-contact regimen that is titrated according to patient tolerance. For example, treatment may begin with concentrations as low as 0.1% or 0.25% applied for 10 to 20 minutes per day, with weekly step-wise increases in duration to reach a total contact time up to one hour [64]. Then, weekly, serial increases in the concentration of anthralin can be performed (eg, 0.5, 1, and 2%) based upon patient tolerance and lesion response.

In the United States, anthralin is commercially marketed only as a 1% or 1.2% cream or a 1% shampoo. Thus, in the outpatient setting in the United States, the initial treatment regimen often consists of 1% or 1.2% anthralin applied for 5 to 10 minutes per day. Subsequently, the application time is titrated up to 20 to 30 minutes as tolerated.

Application to surrounding unaffected skin should be avoided to minimize irritation. For patients with well-defined plaques, petrolatum or zinc oxide may be applied to the surrounding skin as a protectant prior to application. After the desired contact period has elapsed, anthralin should be washed off the treated area [28].

Benefit from anthralin therapy is often evident within the first few weeks of therapy. When administered by patients in the outpatient setting, anthralin appears to be less effective than topical vitamin D or potent topical corticosteroid therapy [33,65,66].

ULTRAVIOLET LIGHT — Ultraviolet (UV) irradiation has long been recognized as beneficial for the control of psoriatic skin lesions. As an example, patients often notice improvement in skin lesions during the summer months. UV radiation may act via antiproliferative effects (slowing keratinization) and anti-inflammatory effects (inducing apoptosis of pathogenic T-cells in psoriatic plaques). In choosing UV therapy, consideration must be given to the potential for UV radiation to accelerate photodamage and increase the risk of cutaneous malignancy.

Phototherapy and photochemotherapy require the supervision of a dermatologist trained in these treatment modalities. The American Academy of Dermatology has provided guidelines for the treatment of psoriasis with ultraviolet light [67]. Despite high efficacy and safety, the use of office-based phototherapy has declined in the United States because of administrative issues [68].

Modalities — Therapeutic doses of ultraviolet light can be administered in several ways:

Phototherapy refers to treatment with ultraviolet B (UVB) radiation (290 to 320 nm). This treatment is used in patients with extensive disease, alone or in combination with topical tar. The mechanism of action of UVB is likely through its immunomodulatory effects [69]. Patients receive near-erythema-inducing doses of UVB at least three times weekly until remission is achieved, after which a maintenance regimen is usually recommended to prolong the remission.

Narrow band UVB (311 nm) is an alternative to standard (broadband- 290 to 320 nm) UVB in the treatment of psoriasis. Suberythemogenic doses of narrow band UVB are more effective than broadband UVB in clearing plaque psoriasis [70]. Apoptosis of T cells is also more common with 311 nm than with broadband UVB. However, the higher cost of narrow band UVB bulbs compared with broadband bulbs currently limits its availability.

Photochemotherapy (PUVA) involves treatment with either oral or bath psoralen followed by ultraviolet A (UVA) radiation (320 to 400 nm) under strict medical supervision. UVA penetrates deeper into the dermis than UVB and does not have the latter's potential for burning the skin. A number of possible mechanisms have been postulated to explain PUVA's effects [71]. With oral PUVA, patients ingest the photosensitizing drug, 8-methoxypsoralen, followed within two hours by exposure to UVA; this sequence is performed three times weekly in increasing doses until remission, then twice or once weekly as a maintenance dose. With bath PUVA, the psoralen capsules are dissolved in water, and affected skin (hands, feet, or total body) is soaked for 15 to 30 minutes prior to UVA exposure. There are few data on the comparative efficacy of oral and bath PUVA for psoriasis. A small open randomized trial of 74 patients with moderate to severe psoriasis did not find a significant difference in efficacy between the two treatments [72]. Additional studies are necessary to confirm this finding.

Some patients take psoralen prior to coming into the office/clinic for PUVA. Increased photosensitivity is typically present starting one hour after an oral dose and resolves after eight hours. Pre and post treatment photoprotection (eg, hat, sunscreen, sun protective goggles) are critical in preventing serious burn injury to the skin and eyes from being outside. (See "Psoralen plus ultraviolet A (PUVA) photochemotherapy".)

Pretreatment emollients have long been thought to improve results with UVB. However, while thin oils do not impede UV penetration, emollient creams can actually inhibit the penetration of the UV and should not be applied before treatment [73]. Gentle removal of plaques by bathing does help prior to UV exposure.

Uncertainty remains about the comparative efficacy of UVB and PUVA phototherapy for plaque psoriasis. Randomized trials comparing the efficacy of narrowband UVB to PUVA have yielded inconsistent findings [74]. The convenience of not needing to administer a psoralen prior to treatment is a favorable feature of UVB phototherapy.

Home phototherapy — An alternative to office-based phototherapy is the use of a home ultraviolet B (UVB) phototherapy unit prescribed by the treating clinician. This option may be preferred by patients who are not in close proximity to an office-based phototherapy center, whose schedules do not permit frequent office visits, or for whom the costs of in-office treatment exceed those of a home phototherapy unit. Home units cost about $3000, but may prove cost-effective in the long term, particularly when compared with biologic therapies. Insurance coverage of these units varies.

For some dermatologists, uncertainty regarding the safety of home units has led to a reluctance to prescribe them. Some have expressed concern for the potential for improper or excessive usage of these devices [75]. In contrast, a randomized trial of 196 subjects found that narrowband UVB administered via home units was as safe and effective as office-based treatments [75]. Home phototherapy units that are equipped with electronic controls that allow only a prescribed number of treatments are available and may help to mitigate clinician concerns.

Excimer laser — Another development in ultraviolet therapy for psoriasis involves use of a high energy 308 nm excimer laser. The laser allows treatment of only involved skin; thus, considerably higher doses of UVB can be administered to psoriatic plaques at a given treatment compared with traditional phototherapy. Uncontrolled trials suggest that laser therapy results in faster responses than conventional phototherapy [76,77]. As an example, one study of excimer laser therapy involved 124 patients with stable mild to moderate plaque psoriasis, of whom 80 completed the entire protocol [76]. Treatments were scheduled twice weekly. After 10 or fewer treatments, 84 and 50 percent of patients achieved the outcomes of 75 percent or better and 90 percent or better clearing of plaques, respectively. This number of treatments was far fewer than that typically required of phototherapy (25 or more). Side effects of laser therapy included erythema and blistering; these were generally well tolerated, and no patient discontinued therapy because of adverse effects.

A common sequela of excimer laser therapy is the induction of UV-induced hyperpigmentation (tanning) in treated areas, which can be cosmetically distressing for some patients. Hyperpigmentation resolves after the discontinuation of treatment.

Like 311 nm UVB, the excimer laser represents a therapeutic advance toward specific wavelength therapies for psoriasis. While both the excimer laser and narrow band UVB are approved for use in psoriasis, inconsistencies in third party coverage for these treatments limit their current utilization.

Cancer risk — A concern with PUVA is an increased risk of nonmelanoma skin cancer and melanoma. Ongoing monitoring is indicated in patients who have received prolonged courses of PUVA. In general, phototherapy is contraindicated in patients with a history of melanoma or extensive nonmelanoma skin cancer. (See "Psoralen plus ultraviolet A (PUVA) photochemotherapy", section on 'Skin cancer'.)

Folate deficiency — Folate deficiency has been associated with health disorders such as neural tube defects in fetuses of affected pregnant women, anemia, and hyperhomocysteinemia (a risk factor for cardiovascular disease). In an in vitro study, exposure of plasma to UVA led to a 30 to 50 percent decrease in the serum folate level within 60 minutes [78]. However, folate deficiency secondary to UVA exposure has not been proven to occur in vivo. In a small randomized trial of healthy subjects, no difference in serum folate levels was identified between subjects irradiated with UVA for six sessions and untreated subjects [79]. In addition, an observational study of 35 psoriasis patients found that narrow band UVB had no effect on serum folate levels after 18 treatment sessions [80].

Saltwater baths — As discussed above, exposure to natural sunlight has been observed to improve psoriasis. Bathing in sea water in combination with sun exposure (climatotherapy) has also been used as a therapy for psoriasis, as has the use of salt water baths with artificial UV exposure (balneophototherapy).

A large, open, randomized trial found that treatment with UVB after a saltwater bath had greater efficacy than UVB after a tap-water bath, and similar efficacy to bath PUVA [81]. Although the raters of disease severity were intended to be blinded, treatment assignment was known to the raters in nearly 60 percent of cases. Additionally, less than half the patients were considered to have met the study's prespecified criteria for having been eligible and treated per protocol. In per-protocol analyses, no difference was found between saltwater and tap-water baths, and bath PUVA was superior to UVB after a saltwater bath.

Additional studies are required to demonstrate that combining saltwater baths with phototherapy is superior to tap-water baths plus phototherapy or to phototherapy alone.

SYSTEMIC THERAPIES — A variety of systemic medications are used for the treatment of psoriasis [82-84], particularly for patients with more than 10 percent body surface area involvement or less extensive, but debilitating disease. In 2008 and 2009, the American Academy of Dermatology published guidelines for the management of psoriasis with systemic therapies [82,83].

Options for systemic therapy include immunosuppressive or immunomodulatory drugs such as methotrexate, cyclosporine, and biologic agents. Systemic retinoids, which improve psoriasis through effects on epidermal proliferation and differentiation as well as immunomodulation, are also used for the treatment of this condition [82].

The efficacies of the various systemic treatments for psoriasis were compared in a 2013 systematic review of randomized trials. Indirect comparisons of the proportion of patients in placebo-controlled trials who achieved at least 75 percent improvement in the Psoriasis Area and Severity Index (PASI) score after 8 to 16 weeks of treatment showed that the efficacy of infliximab within this time period was superior to etanercept, adalimumab, ustekinumab (45 mg dose), alefacept, cyclosporine, and methotrexate [85]. In addition, head-to-head trials included in the systematic review supported the superiority of infliximab and adalimumab over methotrexate therapy and the superiority of ustekinumab over etanercept therapy. Although knowledge of the relative efficacies of systemic treatments for psoriasis is useful, consideration of factors such as drug side effects, patient preference, drug availability, and treatment cost (eg, the high cost of biologic agents compared with conventional therapies) also play an important role in treatment selection.

Methotrexate — The folic acid antagonist methotrexate has been used successfully in the treatment of psoriasis for over 30 years. It is also effective for the treatment of psoriatic arthritis and psoriatic nail disease. Initial thoughts on the mechanism of action centered around the antiproliferative effects of methotrexate on DNA synthesis in epidermal cells; more recent evidence supports the concept that it is the immunosuppressive effects of methotrexate on activated T-cells that controls psoriasis [86].

Methotrexate appears to be less effective than at least some of the biologic agents (see 'Biologic agents' below). In one trial, 271 patients with moderate to severe plaque psoriasis were randomized to receive methotrexate, adalimumab, or placebo [87]. After 16 weeks, the proportion of patients achieving a 75 percent improvement in symptoms with methotrexate was more than that with placebo but less than with adalimumab (36, 19, and 80 percent respectively).

Methotrexate is usually administered in an intermittent low-dose regimen such as once weekly. Similar regimens are currently in use in patients with rheumatoid arthritis. Administration can be oral, intravenous, intramuscular, or subcutaneous; the usual dose range is between 7.5 mg and 25 mg per week. Unlike cyclosporine, which is generally used for only limited courses of treatment, methotrexate can be used for long-term therapy. (See "Use of methotrexate in the treatment of rheumatoid arthritis" and 'Systemic calcineurin inhibitors' below.)

Folic acid, 1 mg daily, protects against some of the common side effects seen with low-dose methotrexate such as stomatitis [88]. Folate does not appear to protect against pulmonary toxicity, and it is uncertain whether it protects against hepatic toxicity; monitoring for bone marrow suppression and hepatotoxicity are necessary during therapy. Concurrent use of other medications that interfere with folic acid metabolism, such as sulfa antibiotics, can increase the toxicity of methotrexate. (See "Major side effects of low-dose methotrexate".)

For patients with one or more risk factors for hepatotoxicity from methotrexate, use of a different systemic drug should be considered. (See 'Hepatotoxicity and liver biopsy' below.)

Hepatotoxicity and liver biopsy — In the past, the American Academy of Dermatology (AAD) recommended that all patients with psoriasis undergo liver biopsy to evaluate for hepatotoxicity after every 1 to 1.5 g of cumulative methotrexate [89]. In 2009, the AAD and the National Psoriasis Foundation updated this recommendation with monitoring guidelines that are dependent upon the presence or absence of risk factors for hepatotoxicity [82,90].

Risk factors for hepatotoxicity from methotrexate include [90]:

History of more than moderate alcohol consumption

Persistent abnormal liver chemistry studies

History of liver disease, such as chronic hepatitis B or C

Family history of inherited liver disease (eg, hemochromatosis)

Diabetes mellitus

Obesity

History of significant exposure to hepatotoxic drugs (other than methotrexate) or chemicals

Absence of folate supplementation during methotrexate therapy

Hyperlipidemia

Patients without risk factors for hepatotoxicity should have liver chemistries drawn every one to three months. If five out of nine serum AST levels are elevated over the course of 12 months, or if the serum albumin level is decreased in the context of normal nutritional status and well-controlled psoriasis, a liver biopsy should be performed.

Liver biopsy should also be considered after a cumulative dose of 3.5 to 4 g of methotrexate has been administered. Once patients have reached this dose, options include proceeding with a liver biopsy, continuing to monitor without a liver biopsy, or discontinuing methotrexate therapy.

In patients with risk factors for hepatotoxicity in whom the decision is made to proceed with methotrexate, a liver biopsy should be performed at or near the beginning of therapy. Since a fair number of patients will discontinue therapy within the first two to six months, it is reasonable to perform the biopsy after this time period. For patients who continue methotrexate, liver biopsies should be performed after every 1 to 1.5 g of cumulative methotrexate.

Retinoids — Systemic retinoids (derivatives of vitamin A) are utilized for patients with severe psoriasis, including pustular and erythrodermic forms, and in patients with HIV-associated psoriasis. The retinoid of choice in psoriasis is acitretin. In a pilot study, 6 of 11 patients with psoriasis and HIV infection achieved good to excellent results with acitretin therapy, with four achieving complete clearing of their skin disease [91]. The usual dose range of acitretin is 25 mg every other day to 50 mg daily.

Acitretin can be used in combination with UVB or PUVA therapy. Used in this way, patients have higher response rates with better tolerance and less UV exposure [92,93].

Monitoring for hypertriglyceridemia and hepatotoxicity are required with retinoid therapy. Common side effects include cheilitis and alopecia. Acitretin is teratogenic; it is only indicated in men and in women of non-reproductive potential. Pregnancy is contraindicated for three years after discontinuing the drug [94].

Systemic calcineurin inhibitors — The T-cell suppressor cyclosporine is effective in patients with severe psoriasis [95,96]. Usual doses are in the range of 3 to 5 mg/kg per day orally. Improvement is generally observed within four weeks.

The use of cyclosporine in psoriasis is based upon multiple studies supporting its status as a highly and rapidly effective treatment [82,97-99]. As an example, a placebo-controlled randomized trial found that after eight weeks of treatment with 3, 5, or 7.5 mg/kg of cyclosporine per day, 36, 65, and 80 percent of patients, respectively, were rated as clear or almost clear of psoriasis [97]. All three regimens were superior to placebo, and patients who received the 5 mg dose were least likely to require dose alterations due to side effects or lack of efficacy.

A few randomized trials have compared the efficacy of cyclosporine and methotrexate, utilizing varying treatment regimens and providing different results. Although a 16-week randomized trial in 88 patients failed to find a significant difference in the effects of cyclosporine (3 to 5 mg/kg per day) and methotrexate (15 to 22.5 mg per week) on moderate to severe plaque psoriasis [100], a subsequent 12-week randomized trial of 84 patients with moderate to severe plaque psoriasis found results that indicated superiority of cyclosporine (3 to 5 mg/kg per day) over methotrexate (7.5 to 15 mg per week) [101]. A smaller trial of patients with severe psoriasis found superior efficacy of methotrexate over cyclosporine (3 to 4 mg/kg per day), but utilized much higher doses of methotrexate than are typically prescribed in clinical practice (0.5 mg/kg per week) [102].

Close monitoring is required since renal toxicity and hypertension are common and often limit the long-term use of cyclosporine in patients with psoriasis. (See "Cyclosporine and tacrolimus nephrotoxicity".)

An investigational oral calcineurin inhibitor, ISA247, has also shown efficacy in randomized trials in patients with moderate to severe plaque psoriasis, and may have less nephrotoxicity than cyclosporine [103].

Biologic agents — Biologic agents are important treatment options for moderate to severe plaque type psoriasis [104-106]. The available biologics for psoriasis have been shown in clinical trials to have excellent short-term and long-term efficacy and favorable tolerability. The biologic therapies available for the treatment of psoriasis include etanercept, infliximab, adalimumab, and ustekinumab. Alefacept, another biologic agent, is no longer marketed. Itolizumab, a biologic agent marketed in India, is not available in the United States.

There is a concern that all TNF-alpha inhibitors have the potential to activate latent infections such as tuberculosis and increased rates of infection have been seen in patients with rheumatoid arthritis treated with etanercept, infliximab, and adalimumab. TNF-alpha inhibitors have also been associated with an increased risk of malignancies, including lymphoma and leukemia, and the development of new-onset psoriasis [107]. (See "Tumor necrosis factor-alpha inhibitors: Risk of bacterial, viral, and fungal infections" and "Tumor necrosis factor-alpha inhibitors and mycobacterial infections" and "Tumor necrosis factor-alpha inhibitors: Risk of malignancy" and "Tumor necrosis factor-alpha inhibitors: An overview of adverse effects".)

Etanercept — The TNF-alpha inhibitor etanercept is of benefit in psoriasis [108-111]. It is approved by the FDA for psoriatic arthritis and for adults with chronic moderate to severe plaque psoriasis. Standard dosing for etanercept for adults is subcutaneous injection of 50 mg twice weekly for the initial three months of therapy, followed by a 50 mg injection once weekly for maintenance therapy.

A randomized trial of etanercept in 652 adult patients with active but stable plaque psoriasis involving at least 10 percent of the body surface area found three doses of subcutaneous etanercept (25 mg weekly, 25 mg twice weekly, 50 mg twice weekly) significantly superior to placebo [109]. After 12 weeks, there was at least a 75 percent improvement in a psoriasis area and severity index (PASI) score in 14, 34, 49, and 4 percent, respectively. After 24 weeks, such an improvement was seen in 25, 44, and 59 percent, respectively (no patients received placebo for more than 12 weeks). Etanercept was well tolerated with adverse events and infections occurring at similar rates in all four groups.

A 12-week randomized trial found similar benefits with subcutaneous etanercept 50 mg twice weekly, and also found that, compared with placebo, patients receiving etanercept had significant improvements in measures of fatigue and depression [112]. Another randomized trial demonstrated efficacy in children and adolescents with moderate to severe plaque psoriasis [113]. The long-term safety of etanercept for psoriasis is supported by a 96-week study of etanercept 50 mg twice weekly [114].

The formation of anti-etanercept antibodies has been reported to occur in 0 to 18 percent of patients treated with the drug for psoriasis [115]. However, in contrast to antibodies against infliximab and adalimumab in patients treated for psoriasis with those agents, the formation of anti-etanercept antibodies does not appear to reduce treatment efficacy [115].

Infliximab — The TNF-alpha inhibitor infliximab is of benefit in patients with moderate to severe plaque psoriasis and appears to generally be well-tolerated [116-119]. In addition, the findings of a systematic review suggest that the onset of action of infliximab is faster than other commercially available biologic agents [120]. Standard dosing for infliximab for adults is intravenous infusion of 5 mg/kg at weeks 0, 2, and 6, followed by every eight weeks thereafter.

The efficacy of infliximab for psoriasis was demonstrated in a multicenter randomized trial in 249 patients with severe plaque psoriasis. Compared with placebo, more patients treated with infliximab 3 mg/kg or 5 mg/kg (given intravenously at weeks zero, two, and six) achieved at least a 75 percent improvement in the PASI score at week 10 (6 percent versus 72 and 88 percent, respectively) [118]. The duration of response appeared to be longer with the higher dose. More patients treated with infliximab had serious adverse events (12 versus 0), including four cases that the authors felt were reasonably related to treatment: squamous cell carcinoma, cholecystitis, diverticulitis, and pyelonephritis with sepsis.

The efficacy of infliximab (5 mg/kg given at weeks 0, 2, 6, 14, and 22) was compared with methotrexate (15 to 20 mg per week) in a 26-week open-label randomized trial in patients with moderate to severe psoriasis (RESTORE1 trial) [121]. At week 16, patients who did not achieve at least 50 percent improvement were able to switch to the alternative therapy. The trial found that patients treated with infliximab (n = 653) exhibited greater improvement (78 versus 42 percent achieved 75 percent improvement in the PASI score by week 16) and were much less likely than patients in the methotrexate group (n = 215) to require switching to the alternative therapy (1 versus 29 percent) [121]. In addition, patients who were transitioned from methotrexate to infliximab fared better than those who switched to methotrexate from infliximab; 73 versus 11 percent achieved 75 percent improvement in the PASI score.

Maintenance therapy with infliximab also appears to be effective [119,122,123]. A randomized trial using the dosing schedule above with infliximab 5 mg/kg through six weeks, but then adding maintenance dosing of infliximab 5 mg/kg every eight weeks through 46 weeks found that 61 percent of patients had at least a 75 percent improvement in the PASI score at week 50 [119]. Infliximab was generally well tolerated. The use of maintenance therapy was further supported by a 50-week randomized trial that found that patients treated with continuous therapy (3 or 5 mg/kg infusion every eight weeks after induction therapy at zero, two, and six weeks) maintained the response to treatment better than patients who received intermittent “as needed” therapy (3 or 5 mg/kg infusions separated by at least four weeks when PASI improvement fell below 75 percent) [122].

In addition to experiencing better maintenance of response, there are some data that suggest that patients who receive continuous maintenance therapy with infliximab may be less likely to experience serious infusion-related reactions than patients who receive intermittent maintenance therapy. In trials comparing the two modes of maintenance therapy, slightly higher rates of infusion-related reactions have been observed among recipients of intermittent maintenance therapy [122,123]. A 128-week randomized trial (RESTORE2 trial) designed to compare the long-term efficacy of continuous maintenance therapy (5 mg/kg of infliximab every eight weeks after induction) and intermittent maintenance therapy (reinduction with up to four 5 mg/kg infusions of infliximab over 14 weeks if more than a 50 percent reduction in PASI improvement occurred) was terminated early (at week 124) due to an observation of a higher proportion of serious infusion-related reactions in the intermittent therapy group (8 of 219 [4 percent] versus 1 of 222 patients [<1 percent]) [123]. The reason for this observation was unclear. Whether other regimens of intermittent maintenance therapy would be less likely to yield infusion reactions remains to be seen.

Studies in psoriasis, inflammatory bowel disease, and rheumatoid arthritis have suggested that the production of antibodies to infliximab may contribute to the loss of response to infliximab in some patients with these diseases [115,124-126]. Anti-infliximab antibodies have been reported to occur in 5 to 44 percent of patients who receive infliximab for psoriasis [115,127]. (See "Tumor necrosis factor-alpha inhibitors: Induction of antibodies, autoantibodies, and autoimmune diseases", section on 'Neutralizing antibodies'.)

Adalimumab — Adalimumab, a humanized monoclonal antibody with activity against TNF-alpha, was originally used for patients with rheumatoid arthritis and is also effective for psoriatic arthritis. (See "Treatment of psoriatic arthritis".) Adalimumab is approved by the FDA for treatment of adult patients with moderate to severe chronic plaque psoriasis who are candidates for systemic therapy or phototherapy. Standard dosing for adalimumab for adults is an initial subcutaneous injection of 80 mg of adalimumab followed by 40 mg given every other week, beginning one week after the initial dose.

Examples of studies supporting the efficacy of adalimumab include:

A randomized trial in 147 patients with moderate to severe plaque psoriasis compared adalimumab by subcutaneous injection 40 mg every other week, 40 mg weekly, and placebo [128]. After 12 weeks, more patients treated with adalimumab every other week or weekly achieved at least a 75 percent improvement in the PASI score (53 and 80 percent, respectively), versus 4 percent with placebo. In an open label extension of the study, improvements were sustained for 60 weeks.

A randomized trial in 490 patients with moderate to severe psoriasis who had achieved a 75 percent improvement in the PASI score after 32 weeks of adalimumab found that continuing adalimumab resulted in a higher percentage of patients maintaining their response at 52 weeks (95 versus 72 percent) [129].

Therapy with adalimumab was superior to methotrexate in a randomized trial involving 271 patients with moderate to severe psoriasis [87]. (See 'Methotrexate' above.)

A randomized trial found that adalimumab was more effective than placebo for the treatment of moderate to severe chronic plaque psoriasis involving the hands or feet [130]. After 16 weeks, disease was cleared or almost cleared in 15 out of 49 patients in the adalimumab group (31 percent) compared with 1 out of 23 patients in the placebo group (4 percent).

Adalimumab may be an effective alternative for patients who fail to respond to etanercept [131-133]. In a multicenter, open-label study, patients who did not improve with 50 mg of etanercept twice weekly (n = 50) or who worsened following a dose reduction of etanercept to 50 mg once weekly (n = 35) were treated with 40 mg of adalimumab every other week [131]. After 12 weeks, psoriasis was cleared or almost cleared in 34 percent (95% CI 20-48) of patients who had failed etanercept and 31 percent (95% CI 15-48) of patients who had disease recurrence on the lower dose of etanercept. Treatment success rates approached 50 percent when adalimumab (40 mg weekly or every other week) was given for an additional 12 weeks.

Formation of antibodies against adalimumab is reported to occur in 6 to 50 percent of patients treated with adalimumab for psoriasis and may reduce the response to therapy [115,127,134]. (See "Tumor necrosis factor-alpha inhibitors: Induction of antibodies, autoantibodies, and autoimmune diseases", section on 'Neutralizing antibodies'.)

Ustekinumab — Ustekinumab is a human monoclonal antibody that targets IL-12 and IL-23. In September 2009, ustekinumab was approved by the US Food and Drug Administration for the treatment of adult patients with moderate to severe psoriasis who are candidates for phototherapy or systemic therapy. Dosing of ustekinumab is weight-based. Standard dosing for ustekinumab for adults ≤100 kg is 45 mg given at weeks 0, 4, and every 12 weeks thereafter. A 90 mg dose given in the same regimen is recommended for adults who weigh more than 100 kg.

A phase 2 randomized trial suggested that ustekinumab is highly effective in the treatment of moderate to severe plaque psoriasis [135], and phase 3 trials have confirmed these results [136-139]:

A randomized trial in 766 patients with moderate to severe plaque psoriasis found that more patients treated with ustekinumab 45 mg or 90 mg achieved at least a 75 percent improvement in the PASI score at week 12 than those treated with placebo (67 and 66 versus 3 percent) [136]. Ustekinumab was administered monthly by subcutaneous injection for the first two doses and then every 12 weeks. Responders who were kept on therapy generally maintained improvements in psoriasis out to at least 76 weeks. Serious adverse events were seen at similar rates in the ustekinumab and placebo arms.

A second similarly designed trial in 1230 patients with moderate to severe plaque psoriasis also found that more patients treated with ustekinumab 45 mg or 90 mg achieved at least a 75 percent improvement in the PASI score at week 12 than those treated with placebo (67 and 76 versus 4 percent) [137]. Patients who achieved a partial response at week 28 were randomly assigned to continue every 12 week dosing or escalate to every 8 week dosing. More frequent dosing did not enhance response rates at one year in patients receiving 45 mg, but did enhance 75 percent improvement rates in those receiving 90 mg (69 versus 33 percent with continued 12 week dosing). Serious adverse events were again seen at similar rates in the ustekinumab and placebo arms.

The efficacy of ustekinumab appears to persist over time. Follow-up data from one of the phase 3 randomized trials above [136] demonstrated maintenance of a high level of drug efficacy over the course of three years [140]. In addition, treatment for up to four years appears to be well-tolerated [140-143].

A randomized trial reported superior efficacy of ustekinumab over etanercept for the treatment of psoriasis [144]. In this trial, 903 patients with moderate to severe psoriasis received 90 mg of ustekinumab at weeks 0 and 4, 45 mg of ustekinumab at weeks 0 and 4, or 50 mg of etanercept twice weekly. After 12 weeks, 75 percent improvement in the PASI score was observed in 73.8, 67.5, and 56.8 percent of patients in the 90 mg ustekinumab, 45 mg ustekinumab, and etanercept groups, respectively. In addition, some patients who did not respond to etanercept benefited from treatment with ustekinumab. Twelve weeks after crossover to 90 mg of ustekinumab (administered at weeks 16 and 20), 48.9 percent achieved 75 percent improvement in the PASI score. The incidence of serious adverse effects was similar between treatment groups.

Data are limited on the best methods for transitioning patients from other therapies to ustekinumab. In a randomized trial (TRANSIT trial) performed in 490 patients with moderate to severe plaque psoriasis who had insufficient responses to methotrexate, measures of the efficacy and safety of ustekinumab after 12 weeks were similar among patients who immediately discontinued methotrexate at the start of ustekinumab therapy and patients who gradually withdrew methotrexate during the first four weeks after starting ustekinumab [145]. Standard doses of ustekinumab were given; patients weighing 100 kg or less and patients weighing more than 100 kg were assigned to 45 and 90 mg doses, respectively. The findings of this study suggest that tapering of methotrexate during the transition to ustekinumab treatment may not be necessary.

Because of its immunomodulatory mechanism of action, there is concern that ustekinumab may increase the risk for infections and malignancy. However, pooled data from phase 2 and phase 3 randomized trials with up to four years of follow-up do not suggest an increase in risk of infection or malignancy in treated patients when compared with expected population rates [143]. Uncommon drug-related adverse effects, such as reversible posterior leukoencephalopathy syndrome and a lymphomatoid drug eruption have occurred in two separate patients [146,147]. (See "Reversible posterior leukoencephalopathy syndrome".)

Although randomized trials have demonstrated efficacy of ustekinumab for psoriatic arthritis, concern has been raised about whether psoriatic arthritis may worsen in certain patients during ustekinumab therapy. A case series documents four patients with psoriasis in whom psoriatic arthritis flared during ustekinumab therapy [148]. (See "Treatment of psoriatic arthritis", section on 'Ustekinumab'.)

Reports of major adverse cardiovascular events during phase 2 and 3 studies for ustekinumab and briakinumab, another anti-IL-12/23 agent, led to the performance of a meta-analysis of placebo-controlled randomized trials evaluating the relationship between anti-IL-12/23 therapy and major adverse cardiovascular events in patients with chronic plaque psoriasis [149]. The meta-analysis found that more major adverse cardiovascular events were reported in patients who received active treatment with ustekinumab or briakinumab than in those who received placebo (10 out of 3179 patients versus 0 out of 1474 patients). Although the difference in events was not statistically significant, the trial lengths were short (12 to 20 weeks), and the meta-analysis may have been underpowered to detect a significant difference.

A review of pooled data from phase 2 and phase 3 trials with up to five years follow-up did not reveal an increased risk for major adverse cardiovascular events [150]. Additional studies are necessary to explore the relationship between these anti-IL-12/23 agents and cardiovascular morbidity.

Anti-ustekinumab antibodies have been reported to occur in 4 to 6 percent of patients treated with ustekinumab for psoriasis; however, an effect of anti-ustekinumab antibody formation on treatment efficacy remains to be confirmed [115].

Alefacept — The recombinant protein alefacept was effective for the treatment of psoriasis [151-153]. However, in late 2011, production and distribution of alefacept was discontinued by the drug manufacturer [154]. The discontinuation of production was neither due to new safety concerns nor a mandatory recall. Alefacept was generally considered to be less effective for psoriasis than other biologic therapies.

Other — Itolizumab, a monoclonal antibody against the T-cell costimulator CD6, is a biologic agent that is available for the treatment of psoriasis in India. Itolizumab is not available in the United States.

The findings of a phase III trial support the superiority of itolizumab compared with placebo for the treatment of moderate to severe plaque psoriasis [155]. However, response rates in the phase III trial were lower than those reported in phase III trials of infliximab, adalimumab, and ustekinumab therapy [119,129,136,137]. The efficacy of itolizumab has not been directly compared with other biologic agents.

Other immunosuppressive agents — Other immunosuppressive agents are sometimes used in selected cases of severe psoriasis [96]. These drugs include hydroxyurea, 6-thioguanine, and azathioprine, which have a place in the treatment of psoriasis when other systemic modalities cannot be used, and tacrolimus, which is similar to cyclosporine and requires larger studies before it can be considered an accepted alternative [82]. Daclizumab, which is used for prevention of renal transplant rejection, and the cancer chemotherapeutic drug paclitaxel are also under investigation for use in severe psoriasis [156,157].

Fumaric acid esters — Fumaric acid esters (fumarates) have been used to treat psoriasis in Northern Europe [158]. In a randomized trial of 60 patients with moderate to severe psoriasis, reductions in disease severity after treatment with fumaric acid esters were similar to those observed with methotrexate therapy [159]. Additional trials of fumarates are being performed.

Lymphopenia is an occasional side effect of treatment with fumaric acid esters. In 2013, two cases of progressive multifocal leukoencephalopathy (PML) were reported in patients who continued to receive long-term fumaric acid ester therapy despite the development of severe lymphopenia [160,161]. These patients did not have other known causes of immunodeficiency.

FUTURE THERAPIES — Interleukins in the Th17 pathway play a pivotal role in the pathogenesis of psoriasis and have become targets for drug development. Drugs such as secukinumab [162-164], briakinumab [165-168], ixekizumab [169], and brodalumab [170] have been developed to target this pathway.

Two 52-week phase III placebo-controlled trials (ERASURE trial and FIXTURE trial) support the efficacy of secukinumab, an anti-IL-17A monoclonal antibody, for moderate to severe plaque psoriasis [162]. In both trials, secukinumab was given as a 300 mg or 150 mg dose once weekly for five weeks, then once every four weeks. In the ERASURE trial (n = 738) a 75 percent reduction in Psoriasis Area and Severity Index (PASI) score at week 12 was achieved by 82 percent of patients in the 300 mg secukinumab group and 72 percent of patients in the 150 mg secukinumab group, compared with only 5 percent of patients in the placebo group. The FIXTURE trial (n = 1306), which incorporated similar doses of secukinumab, found that secukinumab was superior to both etanercept (50 mg twice weekly for 12 weeks, then once weekly) and placebo. After 12 weeks, a 75 percent reduction in PASI score was detected in 77 percent of patients in the 300 mg secukinumab group, 67 percent of patients in the 150 mg secukinumab group, 44 percent of patients in the etanercept group, and 5 percent of patients in the placebo group.

Phase III placebo-controlled randomized trials have supported the efficacy of briakinumab, a monoclonal antibody targeting IL-12/23, in moderate to severe plaque psoriasis, and the drug has exhibited efficacy superior to that of etanercept and methotrexate [165-168]. However, concerns have been raised regarding a potential relationship between briakinumab treatment and major cardiovascular adverse events (see 'Ustekinumab' above) [149]. Marketing plans for briakinumab have been suspended, and it remains uncertain whether the drug will become available for clinical use.

Phase II trials have demonstrated efficacy of an anti-IL-17 monoclonal antibody (ixekizumab) [169], an anti-IL-17 receptor monoclonal antibody (brodalumab) [170], and a humanized anti-TNF monoclonal antibody Fab fragment linked to polyethylene glycol (certolizumab pegol) [171] in moderate to severe plaque psoriasis [169,170].

Other potential therapies include various small molecules that target the interruption of cellular signaling; such signaling is critical to propagation of the inflammatory response. Examples of small molecules that are being studied for the treatment of psoriasis include molecules that block janus kinases (JAK) [172-175], lipids [176], and a protein kinase C inhibitor [177]. Oral tofacitinib, a JAK inhibitor approved and marketed for the treatment of rheumatoid arthritis, demonstrated efficacy for moderate to severe plaque psoriasis in a phase II placebo-controlled randomized trial [174]. In addition, a phase II randomized trial found that a topical formulation of tofacitinib was more effective for plaque psoriasis than vehicle [173].

Apremilast, a phosphodiesterase 4 inhibitor, may be a promising agent for the treatment of psoriasis [178-181]. In a phase II randomized trial of 352 adults with moderate to severe plaque psoriasis treated with apremilast at various doses (10 mg twice daily, 20 mg twice daily, or 30 mg twice daily) or placebo for 16 weeks, patients treated with 20 or 30 mg of apremilast twice daily were significantly more likely to achieve 75 percent improvement in the psoriasis area and severity index (PASI-75) than patients in the placebo group [180]. Among patients treated with 30 mg twice daily, 20 mg twice daily, 10 mg twice daily, and placebo, PASI-75 was achieved by 41, 29, 11, and 6 percent of patients, respectively. These results were supported by a 12-week phase II randomized trial of 259 adults with moderate to severe plaque psoriasis that compared apremilast 20 mg twice daily, apremilast 20 mg once daily, and placebo [181]. Patients treated with the 20 mg twice daily dose of apremilast were more likely to achieve PASI-75 than patients in the placebo group (24 versus 10 percent). A significant difference in response between the apremilast 20 mg once daily and placebo groups was not detected (10 versus 10 percent).

In small, uncontrolled studies, treatment with a glucagon-like peptide 1 (GLP-1) analog (exenatide or liraglutide) has seemed to promote modest improvement in psoriasis in patients with both psoriasis and type 2 diabetes [182,183]. Additional studies are necessary to confirm these findings.

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Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)

Basics topics (see "Patient information: Psoriasis (The Basics)")

Beyond the Basics topics (see "Patient information: Psoriasis (Beyond the Basics)")

The National Psoriasis Foundation is a nonprofit organization that provides useful information to patients with psoriasis and their clinicians. Membership includes access to a newsletter that provides information on current areas of research and new treatments.

 National Psoriasis Foundation

 6600 SW 92nd Ave., Suite 300

 Portland, OR 97223-7195

 1-800-723-9166

www.psoriasis.org

SUMMARY AND RECOMMENDATIONS — Numerous topical and systemic therapies are available for the treatment of psoriasis. Treatment modalities are chosen on the basis of disease severity, relevant comorbidities, patient preference (including cost and convenience), efficacy, and evaluation of individual patient response. (See 'Approach' above.)

We suggest that patients with mild-to-moderate plaque psoriasis be initially treated with topical corticosteroids and emollients (Grade 2B). (See 'Mild-to-moderate disease' above.)

Alternatives include tar, topical retinoids (tazarotene), topical vitamin D, and anthralin. For facial or intertriginous areas, topical tacrolimus or pimecrolimus may be used as alternatives or as corticosteroid sparing agents. Improvement can be anticipated within one or two months. Combination regimens may be required, including localized phototherapy. Patient adherence may be the largest barrier to treatment success with topical therapies; frequent patient follow-up (initially every week) may improve compliance. (See 'Topical therapies' above and 'Ultraviolet light' above.)

We suggest that most patients with moderate-to-severe plaque psoriasis be initially treated with phototherapy if possible (Grade 2B). (See 'Severe disease' above.)

The topical therapies discussed above are generally also required as adjuvant therapy and for symptomatic relief (see 'Topical therapies' above). In patients with contraindications to phototherapy such as history of melanoma or extensive nonmelanoma skin cancer, or in patients with moderate-to-severe disease who also have psoriatic arthritis, we suggest treatment with a systemic agent (Grade 2B). Patients who fail to respond to phototherapy are also candidates for systemic therapy.

Financial considerations or time constraints may also make systemic therapy preferable to phototherapy for some patients. Systemic agents include retinoids, methotrexate, cyclosporine, and biologic immune modifying agents such as adalimumab, etanercept, infliximab, and ustekinumab. Treatment of psoriatic arthritis is discussed in detail separately. (See "Treatment of psoriatic arthritis".)

Improvement should be observed within weeks. Such patients will generally require care by a dermatologist. (See 'Severe disease' above.)

For patients receiving methotrexate for the management of psoriasis, the decision to perform a liver biopsy should be individualized based upon a patient's risk factors, liver chemistry results, and cumulative methotrexate dose, in accord with updated guidelines from the American Academy of Dermatology (AAD). (See 'Hepatotoxicity and liver biopsy' above.)

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