In Japan and parts of Southern Europe, OLP has been associated with hepatitis C infection and chronic liver disease, but these findings have not been reproduced in patients in the US.
Making the diagnosis: exam, biopsy, immunofluorescence
A detailed history and physical examination are usually sufficient to diagnose OLP, although laboratory studies and biopsy may be required to exclude malignancy or distinguish OLP from conditions such as pemphigus vulgaris and mucous membrane pemphigoid. A biopsy is rarely needed, and should only be performed by physicians that have training in a tongue biopsy.
If necessary, biopsy samples should be obtained from the most representative sample area of the tongue. After administration of local anesthesia (lidocaine 1:100,000 with epinephrine) near the periphery of the site, biopsy is performed using a #15 blade scalpel or biopsy punch. An assistant may be needed to grasp the tongue by wrapping a gauze sponge over the tip and securing it firmly. When tongue biopsy sites are closed, deep sutures should be placed if necessary, and mucosal sutures should be placed relatively close together, as inadequately closed wounds on the tongue tend to reopen, resulting in bleeding and prolonged healing time.
Specimens should be placed in a 10% formalin solution for transportation to a pathologist. Patients should return to the clinic after 7 to 14 days for examination of the biopsy site and suture removal.
Microscopically, OLP demonstrates vacuolar degeneration, basal cell lysis, and liquefactive degeneration1 along with focal hyperkeratosis, a characteristic amorphous eosinophilic band at the basement membrane level, and a dense, bandlike subepithelial lymphocytic infiltrate.5,6 Direct immunofluorescence, displaying granular fibrino-gen and variable immunoglobulin deposited linearly near the basement membrane, and possibly cytoid bodies, is useful in cases of suspected OLP with nondiagnostic histological findings, as well as in those with gingival involvement.1
Differential diagnosis
The clinical differential diagnosis of OLP includes the autoimmune bullous diseases pemphigus vulgaris, mucous membrane pemphigoid, dermatitis herpetiformis, and linear immuno-globulin A disease, which can all be excluded with direct and indirect immunofluorescence studies. When clinically appropriate, biopsy specimens submitted for direct immunofluorescence must be preserved in Michel solution. Reactive keratoses, chronic hyperplastic candidosis, epithelial dysplasia, discoid lupus erythematosus, anemic states, and several gastrointestinal diseases including oral Crohn disease and chronic hepatic disease, must also be ruled out.
Oral lichenoid reactions may develop as a hypersensitivity to dental materials and drugs, and must also be considered.1 Patch testing may help identify a contact allergy to dental prosthesis components, including gold, mercury, and palladium salts.