Acne Inversa (Hidradenitis Suppurativa)

Figure 3.3 A: Perioral dermatitis B: Hidradenitis suppurativa C: Fox-Fordyce disease (Courtesy of Dr. Sophie M. Worobec)

• Chronic inflammatory and scarring disease of apocrine gland-bearing skin sites (axillae and anogenital area)
• Initially thought to be due to obstruction of apocrine glands, but now thought to be from occlusion of follicular infundibula with subsequent rupture of the follicle and surrounding inflammation
• Presents with double-ended comedones, tender nodules and sterile abscesses in groin, axillae, perianal and/or inframammary region; sequelae include sinus tracts, chronic drainage, and scarring (hypertrophic scars, rope-like elevation of skin, dermal contractures)
• Histology: follicular hyperkeratosis, rupture of follicular epithelium, heavy inflammatory infiltrate (lymphocytes, neutrophils, plasma cells) around hair follicles ± sweat glands (sometimes extending to apocrine glands), abscess formation, foreign body-type granulomas, fibrosis in late stages
• Treatment: weight reduction, antiseptic soap, absorbent powder, topical aluminum chloride, intralesional corticosteroid injection into early inflammatory lesions, systemic corticosteroids (but typically flare when discontinued), isotretinoin (results often disappointing), acitretin, surgical excision and grafting; avoid incision and drainage (can result in scarring and chronic sinus t ract formation)