An atlas of the morphological manifestations of hidradenitis suppurativa.

This article is dermatological atlas of the morphologic presentations of Hidradenitis Suppurativa (HS). It includes: superficial abscesses (boils, furnucles, carbuncles), abscesses that are subcutaneous and suprafascial, pyogenic granulomas, cysts, painful erythematous papules and plaques, folliculitis, open ulcerations, chronic sinuses, fistulas, sinus tracts, scrotal and genital lyphedema, dermal contractures, keloids (some that are still pitted with follicular ostia), scarring, skin tags, fibrosis, anal fissures, fistulas (i.e. circinate, linear, arcuate), scarring folliculitis of the buttocks (from mild to cigarette-like scarring), condyloma like lesions in intertrigous areas, fishmouth scars, acne inversa, honey-comb scarring, cribiform scarring, tombstone comedones, and morphia-like plaques. HS can co-exist with other follicular diseases such as pilonidal cysts, dissecting cellulitis, acne conglobata, pyoderma gangrenosum, and acanthosis nigricans. In sum, the variety of presentations of HS as shown by these images supports the supposition that HS is a reaction pattern.HS is a follicular based diseased and its manifestations involve a multitude of follicular pathologies [1,2]. It is also known as acne inversa (AI) because of one manifestation that involves the formation of open comedones on areas besides the face. It is as yet unclear why HS is so protean in its manifestations. HS severity is assessed using the Hurley Staging System (Table 1). It also remains unclear why hidradentitis may remain limited to Hurley Stage 1, evolve to the more confluent (Hurley Stage 2), or progress even further to the fully confluent (Hurley Stage 3).In addition, HS can be associated with other follicular based diseases such as pilonidal cysts (PCs) of the sacrum and buttocks, dissecting cellulitis (DC), and acne conglobata (AC), which usually involves the face, chest, When HS occurs with PCs, DC, and/or AC it is referred to as the follicular occlusion triad or tetrad [2]. HS can more rarely be associated with pyoderma gagrenosum (PG) or Crohn disease (CD), other inflammatory diseases of the skin that are not follicular. The reason for this is unclear [2]. What AC, DC, HS, CD, and PG share is that they occur in bacterially rich environments. HS probably occurs with acanthosis nigricans because many HS patients are obese [2]. This concurrence seems under reported.