Lichen simplex chronicus

Definition

Lichen simplex chronicus is a chronic inflammation of the skin (dermatitis) characterized by small, round itchy spots that thicken and become leathery as a result of scratching.

Description

Also termed neurodermatis, lichen simplex chronicus is the result of chronic skin irritation. It occurs in 4-5 out of every thousand people. Initial irritation causes itching, and in turn, itching causes scratching. Scratching leads to further irritation, which damages the skin. The possibility of infection is greatly increased when the outer layer of protective skin is broken. Skin usually repairs itself quickly; however, in the case of lichen simplex chronicus, healing skin causes more itching and more scratching causes a thickening of the skin (lichen). The small skin patches are usually 1-10 in (2.54-25.4 cm) in diameter.

Causes and symptoms

Lichen simplex chronicus is often caused by constant rubbing of the skin. The rubbing begins the chain of events that leads from itching to scratching and then to the presence of leather-like skin patches.

Symptoms are chronic itching which is often accompanied by nervous tension. The appearance of scratch marks and the leathery skin patches can be found anywhere on the body. A prolonged lichen simplex chronicus can result in brown-colored pigmentation at the site of irritation.

Diagnosis

A dermatologist, a physician specializing in the study and treatment of skin disorders, can make a diagnosis after a visual exam.

Treatment

Treatment of the itching is necessary to stop the scratching and resulting skin damage. There are a number of ways to stop itching. Perhaps the most important is to cut fingernails very short. Ice can substitute for the relief of scratching. Heat and fuzzy clothing worsen itching; cold and smooth clothing pacify it. If the itching is persistent, dressings may be applied to the affected areas.

Among the topical medications that relieve itching are a number of commercial preparations containing menthol, camphor, eucalyptus oil, and aloe. Topical cortisone is also available without a prescription. Some preparations also contain antihistamines, which penetrate intact skin poorly. All these medicines work better under occlusion, which means putting a waterproof barrier like a rubber glove or plastic wrap over them. For broken skin, topical antibiotics like bacitracin help prevent infection. These should be used early to forestall further damage to the skin.

Reducing the buildup of thick skin may require medicines that dissolve or melt keratin, the major chemical in skin's outer layer. These keratolytics include urea, lactic acid, and salicylic acid.

Resistant cases of lichen simplex chronicus will often respond to cortisone-like drugs injected directly into the lesions.

Sedatives or tranquilizers may be prescribed to combat the nervous tension and anxiety that often accompanies the condition.

Prognosis

Diligent adherence to treatment is usually rewarded with a resolution of the condition. The original cause of itching may be gone, or it may reappear. Preventive treatment in its early stages will arrest the process.

Prevention

Early, gentler substitutes for scratching can entirely prevent lichen simplex chronicus.

Key Terms

Antihistamine

A chemical that interferes with the action of histamine. Histamine is part of an inflammatory response and helps to cause itching.

Callus

Thickened skin due to chronic rubbing or irritation.

Lesion

Abnormal change in tissue caused by localized disease.

For Your Information

Books

• Habif, Thomas P. "Lichen Simplex Chronicus." In Clinical Dermatology: A Color Guide to Diagnosis and Therapy. St. Louis: Mosby, 1995.

• Parker, Frank. "Skin Diseases of General Importance." Cecil Textbook of Medicine, ed. J. Claude Bennett and Fred Plum. Philadelphia: W. B. Saunders Co., 1996.

• Swerlick, Robert A., and Thomas J. Lawley. "Eczema, Psoriasis, Cutaneous Infections, Acne, and Other Common Skin Disorders." In Harrison's Principles of Internal Medicine, ed. Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.

Source: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Author is J. Ricker Polsdorfer MD.

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