Lichen simplex chronicus involves a cycle in which scratching provokes itching, which provokes more scratching.
It most often affects skin areas that are easier to reach, such as the upper chest, arms, neck, legs, and genital area, and often does not affect skin areas that are more difficult to reach, such as the mid to upper back.
Corticosteroids applied to the skin and measures to relieve itching help, but people should avoid scratching and rubbing the skin.
(See also Overview of Dermatitis.)
Lichen simplex chronicus is caused by chronic scratching or rubbing of an area of skin. The act of scratching triggers more itching, beginning a vicious circle of itching-scratching-itching.
Sometimes the scratching begins for no apparent reason. Other times scratching starts because of a chronic dermatitis or other condition, but the person continues to scratch long after the inciting cause is gone. This persistent itch may involve changes in the way a person's nervous system perceives and processes itchy sensations. Lichen simplex chronicus frequently occurs in people who have anxiety disorders and emotional stress. People who have atopic dermatitis, hay fever, and asthma or who have only atopic dermatitis are particularly susceptible to developing lichen simplex chronicus given their predisposition to itch.
Lichen simplex chronicus can occur anywhere on the body, including the anus (see Pruritus Ani) and the genital area (pruritus of the vulvae or scrotum—see Genital Itching). In the early stages, the skin looks normal, but it itches. Later, dryness, scaling, thickening, and dark patches develop as a result of the chronic scratching and rubbing. This process, called lichenification, causes the skin to resemble leather.
Doctors base the diagnosis of lichen simplex chronicus on the results of a physical examination and sometimes take samples of skin and send them to a laboratory (biopsy). Doctors try to discover any possible underlying allergies or diseases that may be causing the initial itching.
When severe itching occurs around the anus or genital area, the doctor may investigate the possibility of other causes, such as
If a cause for the itch can be identified, it is treated.
A potent corticosteroid ointment is applied to the area. People can increase the effects of the corticosteroid ointment by covering the area with plastic wrap and leaving it on overnight. Commercial surgical tape products that are saturated with a corticosteroid help relieve itching and inflammation and protect the skin from scratching. For small areas, the doctor may inject longer-acting corticosteroids under the skin to control the itching.
Doctors may give antihistamines by mouth. Moisturizing agents (emollients) and capsaicin cream may also be applied to the affected areas.
When this disorder develops around the anus or genital area, the best treatment is a corticosteroid cream.
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