Topic 6: Distinguish HS From Common Mimickers

Common differentials include inflamed epidermoid cysts, nodulocystic acne, furuncles, folliculitis, pilonidal disease, perianal Crohn disease, and Bartholin gland disease.²

Possible diagnosis	May resemble HS	Findings that favor or argue against HS
Folliculitis	Follicular papules or pustules	Folliculitis is usually more superficial. Recurrent deep nodules, tunnels, and characteristic distribution favor HS.
Furuncle or carbuncle	Painful inflammatory nodule or abscess	An isolated event may be infectious. Repeated lesions, especially in intertriginous sites, favor HS.
Inflamed epidermoid cyst	Tender subcutaneous nodule, sometimes with drainage	Epidermoid cyst is often a solitary lesion with a central punctum. Multiple recurrent lesions in characteristic regions favor HS.
Nodulocystic acne	Deep nodules, cysts, comedones, and scarring	Predominant involvement of the face, chest, and back favors acne. HS may coexist with severe acne.
Pilonidal disease	Painful or draining lesion in the gluteal cleft	Pilonidal disease is usually localized to the sacrococcygeal region. Consider concomitant HS if lesions also occur in other characteristic sites.
Cutaneous Crohn or perianal fistulizing disease	Perineal or perianal inflammation and drainage	Specialist analysis of gastrointestinal symptoms and fistula anatomy may be needed for Crohn disease. HS and inflammatory bowel disease can coexist.
Bartholin gland cyst or abscess	Painful vulvar swelling	Look for characteristic unilateral location near the vaginal opening in Bartholin gland disease. Broader recurrent inguinal, pubic, or perineal disease favors HS.

 

Diagnostic pitfall: A positive bacterial culture or temporary response to an antibiotic does not, by itself, exclude HS. Secondary infection may occur, and some antibiotics used for HS also have anti-inflammatory effects.

 

• 

  Folliculitis

• 

  Furuncle

• 

  Epidermoid cyst

• 

  Nodulocystic acne

• 

  Pilonidal cyst

• 

  Crohn disease

• 

  Bartholin gland cyst