A 25 year old man with obesity presents with the skin finding above. He notes the lesions in his axillae, inguinal area, inner thighs, and perianal and perineal skin. He said it started at puberty with solitary, painful nodules lasting several weeks or months. He was diagnosed with "boils" and "furunculosis" at the time. Since then, he's always had a few active lesions; they are intensely painful; he can barely walk or sit without pain. A few of these skin lesions have become infected over the years, developed into abscesses, and ruptured externally, draining pus. That relieves the pain. Healing of these lesions has lead to dense fibrotic bands and indurated thick-scarred plaques.
Challenge: This disease is actually more common in women (3:1) but this was the best picture I found. What's the diagnosis?
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