A Case of Unilateral Idiopathic Gynecomastia Aggravated by Low-dose Finasteride (1mg/day, Propecia(R)) / 대한피부과학회지

Low dose finasteride(1mg/d, Propecia(R)) has been widely used as an effective treatment for male androgenetic alopecia. Finasteride is an inhibitor of 5-alpha-reductase, the enzyme responsible for testosterone metabolism to dihydrotestosteron(DHT). We report a case of painful, unilateral idiopathic gynecomastia aggravated by low dose finasteride for male androgenetic alpopecia. A 23-year-old man started treatment with Propecia(R), 1 mg per day. Two months later he presented with a painful enlargement of his right breast. Treatment was stopped and two months later the clinical manifestration had disappeared.