(See also Overview of Dermatitis.)
Lichen simplex chronicus is caused by chronic scratching 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. Doctors do not know why this happens, but psychologic factors may play a role. The disorder does not seem to be allergic. It usually develops between the ages of 20 and 50.
Symptoms
Lichen simplex chronicus can occur anywhere on the body, including the anus (see Pruritus Ani) and the vaginal area (pruritus vulvae—see Genital Itching), but is most common on the upper chest or back, arms, neck, and legs. In the early stages, the skin looks normal, but it itches. Later, dryness, scaling, thickening, and dark patches develop as a result of the scratching and rubbing. This process, called lichenification, causes the skin to resemble leather.
Diagnosis
Treatment
For the disorder to clear up, people must stop all scratching and rubbing of the area. Standard treatments for itching should be followed. Applying surgical tape saturated with a corticosteroid (applied in the morning and replaced in the evening) helps relieve itching and inflammation and protects 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.
When this disorder develops around the anus or vagina, the best treatment is a corticosteroid cream. Zinc oxide paste may be applied over the cream to protect the area. This paste can be removed with mineral oil.
