Hidradenitis suppurativa is a chronic and relapsing inflammatory disorder of the pilosebaceous glands that tends to occur in apocrine-rich anatomical regions. The inciting event is hypothesized to be occlusion of the follicular infundibulum, followed by follicular rupture associated with a vigorous inflammatory response. The pathologic role of microorganisms is debatable; however, bacteria may play a role in eliciting an autoinflammatory response via the innate immune system.[1,2,3,4,5,6,7]
Hidradenitis suppurativa is part of the follicular occlusion tetrad, which includes dissecting cellulitis of the scalp, acne conglobata, and pilonidal cysts. Owing to the similarities of these conditions, "acne inversa" has been used as an all-inclusive term.
Initially, hidradenitis suppurativa presents as open comedones, often with two or more openings, admixed with tender erythematous papules to nodules. Subsequently, lesions become fluctuant and spontaneously drain, then sinus tracts develop. As the condition progresses, the lesions become more numerous, associated with interconnection of the sinus tracts and significant scarring.
The estimated prevalence of hidradenitis suppurativa in the United States is 1%-2%; however, not all patients seek medical help, often owing to embarrassment.[1,2] The typical age of onset is in the second and third decades. Women are three times more likely than men to have hidradenitis suppurativa; however, men have a greater tendency for atypical locations, have more severe disease, and often have associated acne.[1,2,3,4,5]
Most cases are sporadic, but a familial form with autosomal dominant inheritance has been reported. Less commonly, hidradenitis suppurativa can be seen in patients with rare systemic autoinflammatory syndromes, such as the synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and the pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome.
Because lesions often develop postpubertally, androgens have been postulated to play a role. Most patients have a normal androgen profile[1,2,4]; thus, the defect is hypothesized to lie at the androgen receptor level. Although obesity and smoking are often cited as contributory factors, their role in the pathogenesis has not been established; lifestyle modifications may, but do not necessarily, improve the condition.[1,2,3]
A diagnosis of hidradenitis suppurativa is typically based on characteristic history and clinical morphology. In patients who have an atypical presentation, a biopsy can be performed. Histologically, early lesions show follicular hyperkeratosis and plugging of the infundibulum, followed by follicular dilation and epithelial hyperplasia. Ruptured hair follicles elicit a brisk mixed inflammatory infiltrate, and abscesses often develop. Late lesions show epithelial-lined sinus tracts and scarring.
Cultures do not need to be performed from ruptured lesions because they are often colonized by various bacterial species. Tissue cultures of early intact lesions may provide more information; however, they are frequently sterile.
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Cite this: Elizabeth K. Satter. A 40-Year-Old Man With Painful, Rupturing Lesions - Medscape - Jul 27, 2021.