Xeroderma Pigmentosum (redirected from Light allergy)

xeroderma pigmentosum [‚zir·ə′dər·mə ‚pig·mən′tō·səm]

(medicine)

A genodermatosis characterized by premature degenerative changes in the form of keratoses, malignant epitheliomatosis, and hyper- and hypopigmentation.

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Xeroderma Pigmentosum 

a chronic congenital disease of the skin, first described by the Austrian physician M. Kaposi in 1870.

Xeroderma pigmentosum is a hereditary disease (a recessive genodermatosis) often found in children whose parents are blood relatives. The disease begins in early childhood (at age two or three) with an increased sensitivity of the skin to ultraviolet rays. In the spring, reddish spots (to the size of a bean) appear on the exposed areas of the body (face, neck, hands, forearms, legs, and feet). These later acquire a yellowish brown tint, resembling freckles. The affected skin gradually becomes dry. Small scales form on its surface, sometimes accompanied by cracks and a purulent crust (a result of associated secondary infection). The skin in the affected areas subsequently becomes thin and begins to wrinkle. Distended blood vessels appear on its surface (telangiectases). Depigmented areas appear along with the pigmented spots. Often, warty growths appear around the nidi; these may degenerate into basal-cellular or spino-cellular epitheliomas. For this reason, xeroderma pigmentosum is regarded as a precancerous disease.

The treatment of xeroderma pigmentosum is directed mainly against the tumorous and ulcerous formations, using corticosteroids, short-focus X-ray therapy, electric coagulation, and surgical intervention.

Photodesensitizing preparations, photo-protective creams (containing 10 percent phenyl salicylate and 5 percent quinine), and the salve Fotonem are helpful in preventing appearances of the condition. Exposure to the sun should be avoided (especially during the spring and summer). Regular checkups are recommended.

I. IA. SHAKHMEISTER