“…Systemic therapies include: retinoic acid, cytostatic agents (methotrexate, cyclophosphamide, cyclosporine, α/γ‐interferon), epidermal growth factor receptor inhibitor (erlotinib), glucocorticoids and antihistamines. Topical therapies include intralesional injection (5‐fluorouracil, bleomycin, corticosteroids, methotrexate), topical use (retinoic acid, podophyllotoxin), operation, cryotherapy, radiation therapy and electrochemical treatment . In the present case, oral acitretin was dramatically effective, while the mechanism was still unclear.…”