The classical lesions are bilateral and on the buccal mucosa as white lines or striae often forming a pattern . Patients may have skin lesions and should be asked about them. A biopsy shows keratosis, basement membrane hydropic degeneration and a dense T-cell infiltrate with macrophages hugging the epithelium, the remaining tissue being free of infiltrate. There can be lichenoid reactions due to medications and other things that mimic lichen planus both clinically and microscopically.
Treatment can be topical steroids.