Concepts and controversies in the treatment of cutaneous lichen planus.

Cutaneous lichen planus (CLP) is a chronic autoimmune disease classically associated with severely pruritic, polygonal, violaceous, flat-topped papules and plaques. Subtypes such as hypertrophic and bullous lichen planus and lichen planus pigmentosus have been described. Treatment can be challenging, and prospective controlled studies are lacking. Corticosteroids remain the major options for topical and systemic treatment, although some non-steroidal options exist. Phototherapy, especially with narrow band ultraviolet B (NB-UVB), is effective, but caution must be taken because of the risk of keobnerization. Methotrexate and retinoids are an option for extensive disease, and are relatively well tolerated. Other treatments that have been investigated include sulfasalazine, low molecular weight heparin, griseofulvin, hydroxychloroquine, metronidazole and dapsone.