User:Mr. Ibrahem/Lichen planus

Lichen planus (LP) is a long term inflammatory disease of the skin, nails, and mucous membranes. It generally starts as small bumps which may grown into flat-topped areas up to 1.5 cm in width. The color is typically initially red, becomes purplish, before becoming darker than the surrounding skin. It may be gray-brown in people with darker skin. They may be slightly shinny in nature with fine scales or white lines. These often occur on the back of the hands, inside the wrists, chest, front of the lower legs, mouth, and head of the penis. Often itchiness is present.

While the cause is unknown, it is believed to be an autoimmune disease and activated following a trigger. Risk factors include hepatitis C. Rarely, it runs in families. The diagnosis may be supported by a skin biopsy. A similar condition, known as a lichenoid eruption, may occur due to certain medications, in the mouth due to metals used in dental work, and in graft versus host disease.

There is no cure, though medications may be used to help with symptoms. Initial treatment is generally with steroid cream, such as clobetasol twice per day for two to four weeks. If this is not sufficient lesions may be injected with steroids, such as triamcinolone, or these may be taken by mouth. Other options may include metronidazole, isotretinoin, or methotrexate. In many people the skin lesions resolves without specific treatment within 1 to 2 years; though it may recur. Lesions in the mouth are generally persistent.

Lichen planus is relatively common and occurs globally. The skin is affects by the disease in around 0.3% of males and 0.1% of females; while it occurs in the mount in about 1.5% of males and 2.3% of females. Onset is typically after the age of 20, with those between the age of 30 and 60 most commonly affected. It was first described in 1869 by Erasmus Wilson. The term is from the Greek for "tree moss" and the Latin for "flat".