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Epidemiology, clinical manifestations, and diagnosis of psoriasis

Steven R Feldman, MD, PhD
Section Editors
Robert P Dellavalle, MD, PhD, MSPH
Kristina Callis Duffin, MD
Deputy Editor
Abena O Ofori, MD


Psoriasis is a common chronic inflammatory skin disease most commonly characterized by well-demarcated, erythematous plaques with silver scale (picture 1A-E) and associated with a variety of comorbidities. Other presentations, such as guttate, pustular, erythrodermic, inverse, and nail psoriasis also occur (picture 2A-D). Most cases can be treated in the outpatient setting. Rare, life-threatening presentations are far less common than in the past due to the many highly effective systemic medications now available for treating severe psoriasis. (See "Treatment of psoriasis in adults".)

The epidemiology, clinical manifestations, and diagnosis of psoriatic skin disease will be reviewed here. The pathophysiology and treatment of psoriatic skin disease and issues related to psoriatic arthritis are discussed separately. In-depth discussions of the guttate and pustular variants of psoriasis and psoriasis in children are also available separately. (See "Pathophysiology of psoriasis" and "Treatment of psoriasis in adults" and "Treatment of psoriatic arthritis" and "Pathogenesis of psoriatic arthritis" and "Clinical manifestations and diagnosis of psoriatic arthritis" and "Guttate psoriasis" and "Pustular psoriasis: Pathogenesis, clinical manifestations, and diagnosis" and "Psoriasis in children: Epidemiology, clinical manifestations, and diagnosis".)


Estimates of the prevalence of psoriasis have varied across studies. A systematic review of international population-based studies found wide variation in the global prevalence of psoriasis [1]. The prevalence of psoriasis in adults ranged from 0.91 to 8.5 percent, and the prevalence of the disease in children ranged from 0 to 2.1 percent. Geographic location influences the likelihood of having psoriasis; disease prevalence tends to increase with increasing distance from the equator. A systematic worldwide review found the prevalence of psoriasis ranged from 0.5 to 11.4 percent in adults and 0 to 1.4 percent in children [2].

There is no clear gender predilection for psoriasis [1,3]. Although psoriasis can begin at any age, the disease is less common in children than adults. There seem to be two peaks for the age of onset: one between the ages of 30 and 39 years and another between the ages of 50 and 69 years [1].

The incidence of psoriasis may be increasing. A retrospective study of a cohort of adults reported an increased incidence of psoriasis between the years 1970 to 1974 (50.8 cases per 100,000) and 1995 to 1999 (100.5 cases per 100,000) [4]. Another cohort study assessing the incidence of psoriasis in children also reported increasing incidence, from 29.6 cases per 100,000 to 62.7 cases per 100,000 during the same time periods [5]. However, few other studies report on incidence to confirm these findings. Changes in diagnostic patterns over time also may contribute to increasing rates of diagnosis [4].

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Literature review current through: Nov 2017. | This topic last updated: Jul 20, 2017.
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