Lichen planus is an uncommon, recurrent skin condition that causes itchy, shiny reddish purple spots on the skin; gray-white spots in the mouth; glassy bright red spots on the vulva (the area around the vagina); and small patchy areas of hair loss (scarring alopecia).

The symptoms of lichen planus may begin abruptly or gradually. The initial occurrence may persist for weeks or months, and recurrences can continue over many years.

Lichen planus is not contagious. Although its exact cause is not known, it appears more often after exposure to medicines or chemicals.

Treatment of lichen planus focuses on relieving itching, such as with medicated creams. Severe cases may require prescription medicines taken by mouth or light treatment.