Circumscribed red spots over covered parts of the body may, especially in children, be due to infectious diseases. Parents should carefully examine so-called flea-bites, etc., on the skin of their children, so that there may be no confusion with measles, scarlatina, or German measles. Flea-bites appear as small, red, punctiform and rounded areas, with a markedly white centre and a more delicate, darkish-red surrounding. They are about the size of a pea, and are often furrowed with striped scratches. The swellings caused by the bites of bed-bugs are whitish in the centre, raised, much larger, and more oval in shape. Mosquito-bites form round, whitish, raised marks, surrounded by doughy swellings. In case a blood-vessel has been punctured by the mosquito's proboscis, there appears a pin-point sized, red nodule under the skin, whereas the former type of swelling results when the blood is sucked through the skin. The sting of a bee immediately causes distinct swelling, with marked glistening redness. If the skin be doughy and elastic, and at the same time red, glistening, and tense, it is indicative of a local infection and inflammation. A doughy swelling extending over a large area (especially on the knuckles or on the eyelids) points to the presence of some internal disease, more particularly of the heart or kidneys. In such cases it is necessary to have a physician make a special examination of the urine. Bright, copper-coloured, tongue-shaped areas, combined with high fever and doughy swellings, is suspiciously indicative of erysipelas. Red stripes, in the form of cords, on the arms or legs, point to inflammation of the lymph-vessels. If the skin scales off in large patches, it is possibly a sign of a preceding attack of scarlet fever. Burned, blistered, or abrased parts of the skin likewise heal with desquamation.
Blisters on the skin may be clue to various causes. If the formation of blisters be followed by small ulcers that will not heal, a physician should see the patient at once. So-called " miliary fever " forms white, transparent pimples, varying in size from that of a pin-head to that of a millet-seed ; this affection must not be confused with more solid skin granules appearing at the eyelids (rarely on other parts of the body), and consisting of obstructed sebaceous sacs. By reason of dilatation and blackening of their secretion, the obstructed ducts of sebaceous glands form the so-called blackheads.
Hardenings of the skin (callosities) are formed by circumscribed thicken ing of the cells of the horny layer, as a result of pressure. In this case the cells are no longer desquamated in the normal manner, but remain on the surface and form elevated layers. If the cornification of the skin be pre vented by softening clue to a too profuse secretion of sweat, combined with friction of the skin, abrasions will appear. These abrasions may be so deep as to expose the nether layers of ,the,skin ; and, with the secretion of blood and lymph, they may cause painful soreness. In little children who urinate in their diapers, cleanliness is of the greatest importance, as otherwise the urine may soften the epidermis and transform a large area of the abdominal skin into a bleeding, moist surface. Callosities, or corns, are often removed by softening remedies (soap-baths, salicylic acid, etc.) and by scraping with a knife. See CORNS.
The influence of sunlight causes the development of yellowish-brown blotches (freckles) upon the uncovered parts of the body (face and hands). These blotches are formed by deposits of pigment, and offer great resistance to treatment. The pigment being deposited in the deepest layers of the skin, any remedy applied must first loosen the superficial layers, and then modify the coloration of the deep layer. This effect is accomplished only by very active poisons. Such treatments should, therefore, by undertaken only under the supervision of a physician. More extensive discolorations of the skin are often found in great numbers, especially on the shoulders and back of older persons. These blotches, which are slightly raised, resemble birthmarks, hut are softer and flatter. Mercury salts, in strengths as prescribed by a physician, are most efficacious in eradicating them. Women with fair skin may prevent freckles by wearing a brown veil in the sunshine.
The activity of the sweat-glands is of great importance, because harmful substances are generally excreted with the perspiration. The secretion of very corrosive perspiration may lead to soreness and to the formation of miliary eruption, constituting a very troublesome affection, especially of the feet. Powders containing horacic and salicylic acids are very effective reme dies for perspiring feet. Perspiration of the hands, which is usually nervous in its nature, is most readily removed by improving the tone of the blood vessels. This may be brought about by using cold and hot hand-baths alternately (see p. 258).
Rational care of the skin is indispensable, not only for reasons of attrac tiveness and cleanliness, but also for the preservation of health. The more one bears in mind the need of a uniform activity of the entire skin, the nearer will one he to the natural of proper care of this organ. The skin may be trained to accomincdate itself rapidly to changes of tempera ture, maintaining at the same tine the usual heat of the body. This can be accomplished by systematic exercise of the blood-vessels of the skin. Systematic exposure to the influences of the air is one of the best forms of gymnastics for these blood-vessels. The body is exposed much oftener to air changes than to the effects of moisture. One should, therefore, accustom the body to endure exposure to air-currents of widely varying and rapidly changing temperatures. The muscles of the blood-vessels of the skin may be exercised also with cold water ; but this procedure requires caution, for only those who obtain a healthy reaction after a cold douche are benefited by such a mode of treatment. Hot baths are greatly misused, and may cause much harm. A hot bath causes an over-action of the heart equivalent to that caused by a long walk in mountainous regions. Air-baths at varying temperatures accomplish vastly more for the blood supply of the skin than do water-baths.
Cleanliness is an indispensable hygienic measure if one would take proper care of the skin. Not only the dirt which unavoidably accumulates on the skin must be removed, but also the secretions and scales of the skin itself. This cleansing may be satisfactorily accomplished by washing with soap and water. Soaps used on the skin should be neutral ; that is, they should contain neither free acids nor free alkalies.