Infants and young children are peculiarly subject to this disorder, and, if the disease be not promptly arrested, it will assume the severest form and eventually become chronic. The muscles are soft, the eyes are dull and expressionless, and the little sufferer experiences the most excruciating torments. Frequently the whole body is covered with patches of eczema, the secretions are arrested, and, where the scales fall off, the skin is left dry and feverish.
Eczema has no symptoms proper, since the morbid feelings are due to constitutional debility, of which eczema is the result. The signs of eczema are redness, heat, an itching or smarting sensation, the formation of pimples or vesicles, exudation, incrustation, the separation of the cuticle into scales and a gradual thickening of the skin.
Causes. Three forms of constitutional derangement predispose the system to eczema; nutritive, assimilative, and nervous debility. In the former, there is a diminution of nutritive power, so that the patient becomes weak and emaciated. Assimilative debility is indicated by an impaired digestion and a consequent suppression, or an abnormal state of the secretions. Eczema occasioned by nervous debility, is accompanied by all the morbid conditions incident to irritation and exhaustion of the nervous system. Eczema may be excited by a violation of the rules of hygiene, as undue exposure, or sudden transition from heat to cold, deficient or excessive exercise, impure air, or improper clothing.
Psoriasis. Psoriasis may be defined as a chronic form of eczema. The transition of the last stage of eczema into psoriasis is indicated by a tendency of the inflamed, thickened, scaly skin to become moist when rubbed. It usually appears in patches on various portions of the body. The skin is parched and highly discolored. The hairs are harsh and scanty. The patient is constantly tormented by an unbearable itching sensation and, if the skin is rubbed, it exudes a viscous or sticky fluid. These are the characteristic signs of psoriasis. It generally appears on the flexures, folds and crooks of the joints, the backs and palms of the hands, the arms, and the lower portions of the legs.
Pityriasis. (Branny Tetter, or Dandruff.) This affection is a mild form of psoriasis, from which it may be distinguished by a more superficial congestion or inflammation of the affected parts, the absence of swelling, and the formation of smaller scales, having the form and appearance of fine bran. It generally appears on the scalp, sometimes extends over the face, and, in rare instances, affects the entire surface of the body. The signs peculiar to this disease are slight inflammation, itching, and the formation of minute scales.
Causes. Pityriasis is caused by nutritive debility, and is often associated with erysipelas, rheumatism, and bronchitis.
Lichen. (Papular Rash.) Lichen is a term used to designate an eruption of minute conical pimples, which are more or less transparent, red, and occasion great annoyance. The eruption is attended with a severe, hot, prickling sensation, as if the flesh were punctured with hot needles. The pimples contain no pus, but if opened, they exude a small quantity of blood and serum. This disease more frequently occurs between the ages of twelve and fifty, but occasionally appears during dentition, when it is called "tooth rash." The lichen pimples are sometimes dispersed singly over the skin and gradually subside, forming a minute scale, corresponding in position with the summit of the pimple. When the pimples appear in clusters, there is a diffused redness in the affected part, and, if they are irritated, minute scabs will be formed. Lichen generally appears on the upper portion of the body, as on the face, arms, hands, back, and chest.
The various forms of lichen are designated according to their causes, signs, location, manner of distribution, and the form of the pimples.
Lichen Simplex is the simplest form of this disorder, and is indicated by the appearance of minute pimples, which, when the distribution is general, are arranged like the blotches of measles. Sometimes the eruption is local and bounded by the limits of an article of clothing, as at the waist. In eight or ten days, the cuticle separates into minute scales, which are detached and thrown off; but a new crop of pimples soon appears and runs the same course, only to be succeeded by another, and thus the affection continues for months and even years.