L43: Lichen planus

Lichen planus is a group of conditions that involve chronic, inflammatory reactions affecting the skin, hair, nails, and mucous membranes. It presents itself as purplish, itchy, flat bumps that develop over several weeks. In the mouth, vagina, and other areas covered by a mucous membrane, lichen planus forms lacy white patches, sometimes accompanying painful sores. The exact cause of these reactions remains unknown, but they're likely related to an abnormal response of the immune system. Some factors can exacerbate the condition, such as having certain viral infections, allergies, and genetic predisposition. Although the bumps may be very itchy, try not to scratch or pick at them. Over time, these bumps become scaly and may darken and thicken. In oral or genital forms, it may have a significant effect on quality of life due to the associated discomfort. In most cases, lichen planus resolves on its own with time.