Lichen planus is an uncommon, recurrent skin condition that causes itchy, shiny reddish purple spots on the skin, gray-white spots in the mouth, and small patchy areas of hair loss (atrophic cicatricial 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 during stress, fatigue, or exposure to medications or chemicals. It affects women more frequently than men.

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