—This name is applied to a macular lesion, papillary or tuberculous, marked by the appearance of yellowish spots, occurring singly or in groups, often about the eyelids, but seen anywhere upon the skin. When occurring in papules it is called xanthoma planum; when in nodules, xanthoma tuberosum. There is a variety met with in diabetes which is temporary and usually disappears spontaneously.
Treatment.
—The treatment for xanthomatous patches is either electrolysis or complete excision, under local anesthesia.
Keratosis.
—Keratosis is a term applied to thickening of the normal epidermis, occurring in limited areas, the skin being transformed into tense or almost horny tissue. The form which occurs in elderly individuals is called keratosis senilis. It occurs upon the face, the hands, and forearms, but may be seen on any part of the body. The involved areas become discolored, sometimes by true pigmentation, more often by a deposit of dirt. As long as epithelial reproduction occurs away from the basement membrane the lesions are simple and innocent, but in elderly people it requires but little irritation to provoke a down-growth of epithelium, and then the development of epithelioma is rapid.
Treatment.
—These reduplicated epithelial elements can be kept soft by an application of equal parts of glycerin and liquor potassæ. After being softened they may be easily scraped down to a normal level, but will later reform. If they begin to ulcerate they should be excised. Should excision be declined the area may be treated with the thermocautery or with one of the caustic pastes.
Vascular Growths.
—These have already been mentioned in the chapter on Tumors, under the head of Angioma. So far as the skin is concerned they usually occur in the shape of nevi (called strawberry growths) or the more disseminated form, sometimes involving considerable areas, commonly known as “port-wine marks,” which are essentially cutaneous telangiectases, are almost always of congenital origin, and frequently appear in complete form even at birth. They may occur rapidly or slowly. An isolated nevus should be treated by complete excision. Large vascular areas, or port-wine marks, are best treated by repeated electrolysis. If treated early they are sometimes eradicated by the local use of sodium ethylate.
The so-called nevus pigmentosus, or pigmented mole, is generally of congenital origin, and may or may not be accompanied by vascular changes. It is not infrequently covered with hair, and sometimes forms a patch of considerable size, often upon the face. These lesions occasionally occur in such form as to entitle them to be styled nevus verrucosus or nevus pilosus. Occurring upon the back or trunk they are usually disregarded. When upon the face they should receive surgical treatment.