Oral lichen planus (LP) is a T-cell-mediated inflammatory mucosal disease that can be seen with cutaneous LP or in isolation. It usually affects middle-aged and older adults with a predilection for females (2:1). Lichenoid hypersensitivity reactions in the mouth are often indistinguishable from oral LP, and the two terms are sometimes used interchangeably. In contrast to cutaneous LP, oral LP commonly has a chronic course.

Patients may have few to no symptoms if they have the classic or reticular form of oral LP. Erosive / erythematous and ulcerative oral LP lesions are associated with increased sensitivity to acidic, spicy, and crunchy foods as well as pain. Some patients present with erosive / erythematous and ulcerative lesions on the gingiva, representing the clinical entity known as desquamative gingivitis. Patients with desquamative gingivitis are more likely to have the vulvovaginal-gingival or peno-gingival syndrome with genital involvement in addition to oral involvement. Brushing often causes pain and bleeding, so oral hygiene is generally poor. Up to approximately 40% of patients have cutaneous LP in addition to oral LP.

Medications such as antihypertensive agents, some NSAIDs, sulfasalazine, and carbamazepine are associated with the development of cutaneous and oral LP. Statins have been implicated in cutaneous LP. Oral LP is also associated with hepatitis C. Lesions may also appear locally as a result of hypersensitivity to a contactant (such as amalgam and composite restorations, gold, and cinnamic aldehyde compounds).

Lesions are usually present for months and years and will relapse and remit. There is felt to be potential for malignant transformation to well-differentiated squamous cell carcinoma. There is disagreement in the literature regarding the risk, with up to 5% of individuals with oral LP reported with malignant transformation.

Related topics: Lichenoid drug eruption, Lichen planopilaris