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Hidradenitis suppurativa (acne inversa): Pathogenesis, clinical features, and diagnosis

Lynette J Margesson, MD, FRCPC, FAAD
F William Danby, MD, FRCPC, FAAD
Section Editors
Robert P Dellavalle, MD, PhD, MSPH
Mark V Dahl, MD
Deputy Editor
Abena O Ofori, MD


Hidradenitis suppurativa (HS, from the Greek hidros = sweat and aden = glands) is a chronic inflammatory skin condition that is also known as acne inversa (AI), and historically, as Verneuil's disease [1,2]. Although the name "hidradenitis suppurativa" implies a suppurative disorder that primarily involves sweat glands, increasing knowledge of the pathogenesis of the condition has led to the prevailing theory that HS/AI is a chronic follicular occlusive disease involving the follicular portion of folliculopilosebaceous units (FPSUs).

The primary sites of involvement for HS/AI are the intertriginous skin areas of the axillary, groin, perianal, perineal, and inframammary regions, though HS/AI can occur in any skin area that contains FPSUs. The clinical manifestations vary, ranging from recurrent inflamed nodules and abscesses to draining sinus tracts and bands of severe scar formation. The associated pain, malodor, drainage, and disfigurement that accompany HS/AI contribute to a profound psychosocial impact of the disease on many patients.

Early HS/AI lesions often mimic other disorders; misdiagnosis of HS/AI as recurrent furunculosis or "boils" is common. Prompt recognition of the correct diagnosis is important. An early and accurate diagnosis facilitates the initiation of a treatment plan aimed at minimizing the risk of progression to disabling, end-stage disease.

The pathogenesis, clinical manifestations, and diagnosis of HS/AI will be discussed here. Treatment is reviewed separately. (See "Hidradenitis suppurativa (acne inversa): Treatment".)


Estimates of the prevalence of hidradenitis suppurativa (acne inversa, HS/AI) have varied, ranging from less than 1 percent to 4 percent [3-6]. The first population-based incidence study of HS/AI found an annual age- and sex-adjusted incidence of 6 per 100,000 in a county in Minnesota [7].


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Literature review current through: Sep 2016. | This topic last updated: Aug 22, 2016.
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