Lichen planus (LP) is a chronic inflammatory condition that can affect the skin, nails, hair, and mucous membranes. Though it is relatively uncommon, impacting around 1% of the global population, it can significantly affect quality of life due to its symptoms and complications. Most often, it arises in adults between the ages of 30 and 60 and can persist for months or years.
Lichen planus appears in several clinical forms, including cutaneous lichen planus on the skin, mucosal lichen planus in the mouth or genitals, lichen planopilaris on the scalp and hair follicles, lichen planus affecting the nails, lichen planus pigmentosus, and drug-induced lichenoid eruptions. Each type presents differently but shares a common underlying mechanism: an abnormal immune response in which T-cells attack basal keratinocytes in the skin and mucosal tissue.
The exact cause of lichen planus remains unclear, but researchers know it is an autoimmune condition. Certain factors appear to contribute, including genetic predisposition, stress, physical trauma to the skin (known as the Koebner phenomenon), systemic infections such as hepatitis C, and exposure to certain drugs like quinine or gold salts. In some cases, oral lichen planus may be linked to allergic reactions to dental fillings. Vitamin D deficiency has also been noted as a possible contributor, especially in oral disease.
Lichen planus can appear in many ways depending on the site of involvement. Cutaneous LP usually presents as purple, polygonal, flat-topped papules or plaques, sometimes with a fine network of white streaks called Wickham striae. These lesions are most commonly seen on the wrists, ankles, and lower back and can cause significant itching.
Oral lichen planus affects up to half of patients, usually manifesting as white, lacy streaks inside the cheeks or on the tongue. In erosive forms, it can be painful and may lead to ulcers or gum involvement. Lichen planopilaris affects the scalp, leading to scarring alopecia if untreated, while nail lichen planus can cause thinning, ridging, discoloration, or even permanent nail loss. In all forms, the course is typically chronic and relapsing, with pigmentation changes that may persist long after lesions resolve.
Although lichen planus is generally benign, chronic erosive forms—particularly in the mouth or genital region—can increase the risk of squamous cell carcinoma. Esophageal lichen planus may cause swallowing difficulties and strictures, while nail and scalp involvement may result in permanent scarring. For this reason, timely diagnosis and ongoing monitoring are essential.
Diagnosis is primarily clinical, based on the characteristic appearance of lesions. A skin or mucosal biopsy may be recommended to confirm the diagnosis or rule out malignancy. Histology typically reveals irregular thickening of the epidermis, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction.
The management of lichen planus depends on the site and severity of disease. Mild cutaneous forms may be self-limiting and require little beyond emollients and symptomatic itch relief. More symptomatic cases often require potent topical corticosteroids, calcineurin inhibitors like tacrolimus, or intralesional steroid injections.
For more extensive disease, systemic therapy may be prescribed, including oral corticosteroids, topical and oral roflumilast, acitretin, hydroxychloroquine, methotrexate, azathioprine, or mycophenolate mofetil. Phototherapy is another valuable treatment, though it should be avoided in actinic forms that are worsened by sun exposure. Oral lichen planus may sometimes respond to advanced systemic medications, including biologics such as adalimumab or tildrakizumab, JAK -inhibitors especially in severe erosive cases.
Supportive measures are equally important. Avoiding harsh soaps, reducing stress, treating any underlying infections, and ensuring adequate sun protection can all help reduce flares.
The Centre for Medical and Surgical Dermatology (CMSD) in Pickering, led by board-certified dermatologist Dr. Breslavets, offers comprehensive care for chronic inflammatory skin conditions such as lichen planus. Patients undergo thorough evaluations that take into account not only the type and severity of their condition but also its effect on their overall health and quality of life.
