Lichen planus is a recurrent, pruritic, inflammatory eruption characterized by small, discrete, polygonal, flat-topped, violaceous papules that may coalesce into rough scaly plaques, often accompanied by oral and/or genital lesions. Diagnosis is usually clinical and supported by skin biopsy. Treatment generally requires topical or intralesional corticosteroids. Severe cases may require phototherapy or systemic corticosteroids, retinoids, or immunosuppressants.
Etiology of Lichen Planus
Associations of oral lichen planus with hepatitis (hepatitis B infection, , and, particularly, hepatitis C–induced liver insufficiency) and primary biliary cholangitis (formerly known as primary biliary cirrhosis) have been reported.
Symptoms and Signs of Lichen Planus
Typical lesions are pruritic, violaceous (purple), polygonal, flat-topped papules and plaques. Erythema may look more purple or brown on dark skin than on light skin. Lesions initially are 2 to 4 mm in diameter, with angular borders and a distinct sheen in cross-lighting.
They are usually symmetrically distributed, most commonly on the flexor surfaces of the wrists, legs, trunk, glans penis, and oral and vaginal mucosae but can be widespread. The face is rarely involved. Onset may be abrupt or gradual.
Children are affected infrequently.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image provided by Thomas Habif, MD.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image courtesy of Karen McKoy, MD.
Image provided by Thomas Habif, MD.
During the acute phase, new papules may appear at sites of minor skin injury (Koebner phenomenon), such as a superficial scratch. Lesions may coalesce or change over time, becoming hyperpigmented, atrophic, hyperkeratotic (hypertrophic lichen planus), or vesiculobullous. Although pruritic, lesions are rarely excoriated or crusted. If the scalp is affected, patchy scarring alopecia (lichen planopilaris) may occur.
The oral mucosa is involved in about 50% of cases; oral lesions may occur without cutaneous lesions. Reticulated, lacy, bluish white, linear lesions (Wickham striae) are a hallmark of oral lichen planus, especially on the buccal mucosae. Tongue margins and gingival mucosae in edentulous areas may also be affected. An erosive form of lichen planus may occur in which the patient develops shallow, often painful, recurrent oral ulcers, which, if long-standing, rarely become cancerous. Chronic exacerbations and remissions are common.
Vulvar and vaginal mucosae are often involved. Up to 50% of women with oral mucosal findings have undiagnosed vulvar lichen planus. In men, genital involvement is common, especially of the glans penis.
Nails are involved in up to 10% of cases. Findings vary in intensity with nail bed discoloration, longitudinal ridging and lateral thinning, and complete loss of the nail matrix and nail, with scarring of the proximal nail fold onto the nail bed (pterygium formation).
Diagnosis of Lichen Planus
Clinical evaluation
Biopsy
Although the diagnosis of lichen planus is suggested by appearance of the lesions, similar lesions may result from any of the papulosquamous disorders, cutaneous lupus erythematosus, and secondary syphilis, among others.
Oral or vaginal lichen planus may resemble leukoplakia, and the oral lesions must also be distinguished from candidiasis, carcinoma, aphthous ulcers, pemphigus, mucous membrane (cicatricial) pemphigoid, and chronic erythema multiforme.
Typically, biopsy is done.
If lichen planus is diagnosed, laboratory testing for liver dysfunction, including hepatitis B and C infections, should be considered.
Treatment of Lichen Planus
Local treatments
Systemic treatments
Sometimes light therapy
Asymptomatic lichen planus does not require treatment. Medications suspected of triggering lichen planus should be stopped; it can takes weeks to months after the offending medication has been stopped for the lesions to resolve.
Local treatments
Few controlled studies have evaluated treatments. Options differ by location and extent of disease.
Systemic treatments and phototherapy
Oral lichen planus
Other treatment options include topical (in an adhesive base), intralesional, and systemic corticosteroids.
Cyclosporine rinses also may be helpful.
Treatment references
1. Viswanath V, Joshi P, Dhakne M, et alClin Cosmet Investig Dermatol 15:2593-2600, 2022. doi: 10.2147/CCID.S390591
2. Mital R, Gray A, Minta A, et al: Novel and off-label biologic use in the management of hidradenitis suppurativa, pyoderma gangrenosum, lichen planus, and seborrheic dermatitis: A narrative review. Dermatol Ther (Heidelb) 13(1):77–94, 2023. doi: 10.1007/s13555-022-00860-5
Prognosis for Lichen Planus
Many cases resolve without intervention, presumably because the inciting agent is no longer present. Recurrence after years may be due to reexposure to the trigger or some change in the triggering mechanism.
Vulvovaginal lichen planus may be chronic and refractory to therapy, causing decreased quality of life and vaginal or vulvar scarring.
Oral mucosal lesions usually persist for life.
Key Points
Lichen planus (LP) is thought to be an autoimmune disorder in patients with a genetic predisposition but may be caused by medications or be associated with disorders such as hepatitis C.
LP is characterized by recurrent, pruritic papules that are polygonal, flat-topped, and violaceous and can coalesce into plaques.
Oral and genital lesions can develop, become chronic, and cause morbidity.
Diagnose LP by clinical appearance and, if necessary, biopsy.
Treat localized LP with topical or injected corticosteroids.
Treat generalized LP with oral medications or phototherapy.
