Lichen planus is an inflammatory disease that usually affects the skin, the mouth and sometimes both. The cause of lichen planus is not known, however there are cases of lichen planus-type rashes (known as lichenoid reactions) occurring as allergic reactions to medications for high blood pressure, heart disease and arthritis.
- Lichen planus has been reported as a complication of chronic hepatitis B and C virus infection, but it can occur for no reason and unrelated to any underlying viral condition.
- The commonly affected sites are the buccal mucosa in the mouth (the inner lining of the cheeks) the wrist skin and the ankle skin. The rash tends to heal with prominent blue-black or brownish discoloration that can persist for a long time if not treated. Besides the typical lichen planus lesions, other varieties of the rash may occur.
- The typical rash of lichen planus can be summarized with 5 “P’s”: Pruritic (itchy), Planar (flat surface, like a plateau), Purple, Polygonal (non-circular, straight edges) Papules (small raised skin bumps).
- On the contrary, when lichen planus occurs inside the mouth, it looks like lacy white streaks that overly bright red oral tissues. Inside the mouth, the disease may present in the reticular form or in the erosive form. The reticular form is the more common presentation and manifests as white lacy streaks on the mucosa (known as Wickham's striae). The lesions tend to be bilateral and are asymptomatic. The lacy streaks can also be seen on the gingiva (gums), the tongue, palate and lips.
- Erosive lichen planus presents with red areas in the mouth or on the genital skin that are ulcerated and uncomfortable. A biopsy is necessary to differentiate lichen planus from other ulcerative conditions of the mouth.
- Currently there is no cure for lichen planus but there are certain types of medicines used to reduce the effects of the inflammation (topical and oral steroids, hydroxychloroquine, dapsone, topical and oral immunosuppressant drugs). Lichen planus may go into a dormant state after treatment.
- Lichen Planopilaris is the name given to lichen planus when it occurs on the scalp. Lichen Planopilaris may cause permanent, scarring hair loss (alopecia). It initially presents as a redness and scale around hair follicles. If left untreated scarring occurs and creates permanent hair loss. The treatments for lichen planopilaris are the same as those mentioned above for lichen planus.