Lichen Planus is an inflammatory skin and mucosa disease with a strong immunopathogenic side. Its cause is unknown. Lilac colored, itchy, ring shaped papules with flat tops may be developed. And their surface may look like White lace. There may be one or more papules.
In the 30% of patients, a White web in the mouth mucosa is present. Lesions also may occure in the genital region. 
It has micro papillary and hypertrophic forms. Occasionally scalp involvement causes alopecia. It can be seen on the nails. 
There is a histological damage in the basal layer. Significant lymphocyte and histiocyte accumulation occurs in the forms of civatte strings and sub epidermis band. It is thought to be an autoimmune disease.

Treatment with topicalcorticosteroids may help prevent itching, but the disease may heal by itself.