Lichen planus affects skin of all types, especially moist skin surfaces (mouth and genital area).
Many conditions are believed to be part of the lichen planus family; the exact causes are unknown. These conditions are often named by the body areas they affect and/or the skin changes they create:
Classic lichen planus causes red to slightly violet flat-topped bumps, usually very itchy, on regular skin with little white stripes over them.
Lichen planus of the nails can cause thin nails, scarring, and even complete loss of the nail.
Oral and vaginal lichen planus occur on the moist surfaces of the mouth and vagina, where inflammation caused by the disease often leads to surface skin layers falling off, leaving raw open areas. These erosions are very painful. If a woman has oral lichen planus, almost half the time she will also have vaginal lichen planus.
Penile lichen planus can also cause erosions and scarring, but usually resembles classic lichen planus.
Lichen planus pigmentosus occurs in persons of color—from the Indian subcontinent, Central America, and the Middle East primarily. Sometimes triggered by sunlight, it does not usually itch but mostly turns the skin gray.
Lichen planopilaris attacks hair follicles on the scalp leaving scarring and permanent baldness. It can occur in the center of the scalp, along the frontal hair line, and in the eyebrows. It can be asymptomatic or itchy and might cause scalp burning.
Skin eruptions caused by commonly used medications can resemble lichen planus. Quinine in tonic water and over-the-counter leg cramp medicines can cause a lichen planus–like condition. In the mouth, allergy to the metals in fillings and oral appliances can cause sores that look exactly like oral lichen planus. Hepatitis C virus infection and hepatitis B immunization can be associated with lichen planus.
All types of lichen planus are diagnosed by skin biopsy. Classic lichen planus often goes away after a few months or years, although it may return. If caused by medication or fillings, lichen planus will clear after the treatment is stopped or the fillings removed. Lichen planus of the mouth, vagina, nails, and scalp rarely clears by itself and can cause permanent scarring.
If the lichen planus is on the regular skin and not very severe, treatment is often not needed. If the lichen planus is caused by the sun (some cases of lichen planus pigmentosus), a strong sunscreen (sun protection factor [SPF] 50 or higher) should be used daily. For symptomatic lichen planus, topical creams may be effective. In some severe cases, oral medications or light therapy can be useful.
American Academy of Dermatologyhttps://www.aad.org/dermatology-a-to-z/diseases-and-treatments/i---l/lichen-planus
Conflict of Interest Disclosures: None reported.
Berger TG. Lichen Planus. JAMA Dermatol. 2015;151(3):356. doi:10.1001/jamadermatol.2014.5522