Slide show: Common skin rashes

Lichen planus (LIE-kun PLAY-nus) is an inflammatory condition that can affect your skin and mucous membranes. On the skin it usually appears as purplish, often itchy, flat-topped bumps (lesions). In your mouth, vagina and other areas covered by a mucous membrane, lichen planus forms lacy white patches.

The condition may develop gradually over a couple of months. After that, it rarely worsens, but it may persist for months or years. You can usually control mild lichen planus symptoms on the skin, such as stinging and itching, by applying cool compresses or aloe vera gel. More-severe symptoms may require drug treatment. Lesions on mucous membranes tend to take longer to heal and often recur.