Progesterone dermatitis is a rare condition characterized by a cyclic skin rash which develops premenstrually in women. The condition usually occurs in adulthood after the start of periods (menarche), and rarely during pregnancy or postmenopause. Signs and symptoms vary among affected individuals; skin findings that have been reported include hives, erythema multiforme, papulovesicles (an eczema-like rash), annular erythema, angiodema, mouth erosions and pruritus (itching). The rash typically begins a few days before menses and subsides around the time menstruation begins, recurring at the next cycle. The exact cause is unknown, but is thought to involve a hypersensitivity or autoimmune reaction to a woman’s own progesterone. Depending on the severity, treatment may include topical medications, systemic corticosteroids, hormone therapy to inhibit the production of progesterone, or surgical removal of the ovaries.