Atrophia Cutis.
Atrophy of the skin, or atrophia cutis propria, in its various forms is not infrequently encountered. It may occur as an idiopathic affection, or as a symptom in connection with other well-known diseases. Thus, as an example of the former condition the well-known striæ atrophicæ may be cited, while lupus, syphilis, and tinea favosa are sometimes followed by symptomatic atrophy. Injuries to nerves are also at times followed by more or less cutaneous atrophy, usually in connection with wasting of the subcutaneous structures, the skin becoming thin, dry, shrivelled, and yellowish or brownish in color. Atrophy of the skin may be general, as in the senile form, or localized, as in morphoea. Where degenerative atrophy exists the skin is usually somewhat hardened, yellowish or whitish in color, and has a waxy, fatty appearance. In the condition known as glossy skin, generally seen upon the fingers, the skin is reddish, smooth, and shining as though varnished, the affection resembling chilblains. The hairs are usually shed, and excoriations or fissures often exist. It is accompanied with pain of a burning character.
Cases of general idiopathic atrophy of the skin have from time to time been reported, the disease in almost all instances being more marked in some localities than in others, occurring in the form of more or less extensive patches. The disease originally described by Hebra and Kaposi with the name xeroderma, or parchment-skin disease, may here be referred to. The lesions consist of numerous disseminated pigment-spots, resembling freckles; telangiectases, or minute congeries of blood-vessels; atrophic macules of variable size; with more or less shrinking and contraction of skin, followed in most cases by epitheliomatous tumors and ulceration. The disease almost invariably begins in early years, is prone to show itself in several children of the same family, and lasts during life. The advanced stages of scleroderma and morphoea likewise show marked atrophic changes, which, however, will be considered in speaking of those diseases.
Senile Atrophy.—This form of atrophy, taking place as the result of old age, may be simple or degenerative, both usually occurring together. The integument becomes thin and wasted, the surface being dry, wrinkled and more or less discolored by pigmentation, with loss of hair. In degenerative atrophy the connective tissue of the corium becomes changed into a fine or coarse granular matter or into a homogeneous vitreous mass. Fatty metamorphosis and marked pigmentary deposits are also common.
Maculæ et Striæ Atrophicæ.—Atrophic streaks and spots may occur idiopathically or symptomatically. The idiopathic form is that most frequently encountered, and occurs without known cause, generally making its appearance insidiously. It is characterized by lines or streaks constituting the so-called linear atrophy, striæ atrophicæ; or by spots, maculæ atrophicæ. The streaks are more frequently met with, and consist of irregular curved or tortuous lesions, usually about a line in width and of variable length, running parallel with one another. The macules are rounded or ovalish, varying in size from a pinhead to a finger-nail. Both are smooth and glistening, and the skin is thinned and scar-like. They are slightly depressed or grooved, and possess a pinkish, whitish, or bluish-gray color. They may appear upon any region, but the abdomen, buttocks, and thighs are the favorite localities. They pursue a slow course over a period of years or a lifetime, occasioning no inconvenience. The first stage of either variety of the disease is characterized by erythema, the lesion being reddish, hyperæmic, and slightly raised or puffed. This sooner or later disappears, followed by depression and atrophy.
The symptomatic form of the affection is usually noted to take place as the result of extreme distension of the cutaneous structures. It occurs sometimes in obese subjects, and in the latter stages of pregnancy upon the abdomen and mammæ, and over large abdominal and other tumors where the skin is greatly stretched, constituting the so-called lineæ albicantes.
CLASS VI.—NEW GROWTHS.6
6 Lepra (leprosy), an important disease of this class, appears, in Vol. I. p. 785, as a separate article by J. C. White.