This is an inflammatory disease that affects the skin and the oral mucosa. 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.
Symptoms
Itching in a location mild to severe
"¢ Skin lesion:
o Usually located on the inner areas of the wrist, legs, torso, or genitals
o Generalized, with symmetric appearance
o Single lesion or clusters of lesions, often at sites of skin trauma
o Papule of 2 to 4 cm size
o Papules clustered into a plaque or large, flat-topped lesion
o Distinct, sharp borders to lesions
o Possibly covered with fine white streaks or linear scratch marks called Wickham's striae
o Shiny or scaly appearance
o Color dark -- reddish-purple (skin) or gray-white (mouth)
o Possibility of developing blisters or ulcers
"¢ Ridges in the nails (nail abnormalities)
"¢ Dry mouth
"¢ Metallic taste in the mouth
"¢ Mouth lesions
o Tender or painful (mild cases may have no discomfort)
o Located on the sides of the tongue or the inside of the cheek
o Occasionally located on the gums
o Poorly defined area of blue-white spots or "pimples"
o Linear lesions forming a lacy-appearing network of lesions
o Gradual increase in size of affected area
o Lesions occasionally erode to form painful ulcers
"¢ Hair loss

