This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Linear lichen planus (LLP) is a rare form of lichen planus, which is a condition that affects the skin and/or mouth. In LLP, specifically, affected people develop itchy, purple, flat-topped papules (bumps) in a linear distribution along the lines of Blaschko. Although these papules can be found anywhere on the body, they most commonly affect the limbs (arms and legs). The exact underlying cause of LLP is unknown; however, it has been associated with metastatic cancer, HIV infection and hepatitis C infection. Treatment is not always necessary as some cases of LLP resolve on their own. Mild cases can often be managed with topical steroids, while more intensive therapies may be required for severe cases.
For more information, visit GARD.