There is no cure or specific therapy for lichen planus. However, it is usually mild and may require no treatment. Treatment generally concentrates on reducing the itching and inflammation and speeding the healing time of the lesions. Lichen planus that affects mucous membranes is typically more severe than when it affects the skin. The mucous condition may be more persistent and difficult to treat.

If the onset of lichen planus was linked to chemical exposure, it will typically clear up once this exposure has been discontinued. Further outbreaks can be prevented by avoiding the chemical cause.

Antihistamines may be used to provide comfort and relief from itching. Topical treatments for the lesions often begin with bland emollients and detergent-free soap substitutes. Corticosteroid creams and ointments are frequently prescribed to reduce inflammation and suppress immune and allergic reactions. Other topical treatments include topical retinoids and other anti-inflammatory and anti-pruritic creams to reduce itching and inflammation and to aid in healing. Dressings may be used over these topical treatments to increase absorption and protect the affected area from scratching.

Corticosteroids may be injected directly into the lesions to ease itching. Though this can be helpful, caution must be used in people with dark skin, because it may cause hypopigmentation (lighter patches of skin) around the injection site. Oral steroids may be recommended when the scalp is involved.

If mouth lesions are present, an anesthetic mouth wash may be used to temporarily numb the area and make eating more comfortable.

For severe cases, particularly with mucosal involvement, systemic corticosteroids may be used. Other medications for severe, resistant cases include topical immunosuppressants and oral antifungal and anti-inflammatory medications. In some cases, phototherapy, which uses ultraviolet light to treat the skin, may be beneficial.

Because its cause is not known, lichen planus cannot be prevented.