Skin lesions of lichen planus consist of pruritic
(itching), erythematous to light purple patches,
sometimes with an overlying network pattern
of white lines or striations. Oral lesions most
commonly appear as white epithelial thickening
arranged in a network pattern (Wickham's striae)
with erythema of the surrounding mucosa. White
patches, erythematous erosions, and ulcers may
also occur. The white lesions are not painful,
but the erosions and ulcers are usually painful.
Lichen planus almost always has multiple lesions
bilaterally, with the buccal mucosa commonly
involved. Oral lesions may occur with or without
skin lesions.