Inflamed Epidermal Cyst — SCE Dermatology MCQ

Correct answer: C — Incision and drainage — the inflammation is usually caused by foreign body reaction to ruptured cyst contents (keratin) rather than bacterial infection; antibiotics alone are insufficient without drainage

Inflamed epidermal cysts are most commonly caused by cyst rupture with leakage of keratin into the dermis, causing a sterile foreign body granulomatous inflammatory reaction — NOT bacterial infection. Treatment is incision and drainage of the inflammatory contents. Antibiotics alone (without drainage) are insufficient and do not address the retained keratin causing the inflammation. Once the acute inflammation settles (4-6 weeks), the residual cyst wall can be excised electively to prevent recurrence. Excision during active inflammation is technically more difficult (inflamed tissue planes obscure the cyst wall) and has higher recurrence rates. True secondary bacterial infection can complicate ruptured cysts but is less common than sterile rupture.

Reference: BAD; Dermatological Surgery