Ec'zema (Gr., from ekzeo, 'I boil over') is in this country by far the commonest of all diseases of the skin, and also the most variable in its manifestations. It may be acute or extremely chronic, may affect any portion of the skin, and may occur at any age from infancy to old age.
In typical acute eczema the affected portion of skin is red, and is covered with numerous small papules, which speedily turn into vesicles. These may quickly dry up, but more commonly break, and discharge a clear, glutinous secretion, which hardens and forms scabs or crusts, or if copious keeps the surface in a moist 'weeping' condition. In some cases the vesicles are replaced by pustules, and the discharge is partly purulent. Chronic eczema may follow the acute form, or may arise without an acute stage. Here the skin is thickened and hard, and covered with crusts or scales; deep cracks are sometimes present, especially where the skin is subjected to much movement, as near the joints.
One of the most prominent and important symptoms is itching of the part affected; it is never entirely absent, and in some cases intolerably severe, but in the acute stage is often replaced by a burning sensation; it may precede any visible sign of the disease, and may persist after the skin has resumed its natural appearance. The scratching which it occasions always aggravates the disease, and is often very difficult to prevent. Except in extensive acute attacks, there is no fever and very little constitutional disturbance. The disease is not contagious. When cured it leaves no scar.
Causes of Eczema.—In many cases it is very difficult, perhaps impossible, to assign a definite cause for an attack. Generally speaking, however, the constitutional or predisposing cause is some defect in the digestion or assimilation of the food; strumous and gouty individuals are particularly subject to the disease. The local or exciting cause may be anything whatever which irritates the skin—e.g. great heat or cold, rough underclothing, bad soap, hard water, arsenical dyes, lice or other parasites, and the scratching they occasion.
Treatment.—There is no specific for eczema; different cases and different stages of the disease require widely different management, and each must be considered and treated on its own merits. Usually both local and constitutional treatment are required to effect a cure. It is of the greatest importance to seek for and attend to any cause which may have given rise to it. The diet must be nutritious, but as simple and unirritating as possible; digestion may require aid from medicines; the bowels should be regularly evacuated, by aperients if necessary; a gouty or strumous tendency if present must be counteracted. In obstinate chronic eczema small doses of arsenic are often useful. The use of soap on the part affected must be discontinued, and strained oatmeal gruel, or rice water, or white of egg with boiled water, used for cleansing purposes, but even these as seldom as possible. Thorough removal of scales and crusts by these means, or by oil, or simple bread poultices, is the necessary preliminary to satisfactory local treatment. In the acute stage, where the swelling is great or the discharge profuse, a sedative lotion applied on rags or lint and kept moist by a waterproof covering is generally most useful—e.g. thin starch or gruel with a teaspoonful of boracic acid to the pint, soft water with a similar proportion of baking-soda, or dilute lead lotion. In the later stages, when the skin is moist, soothing ointments are preferable—e.g. zinc ointment, zinc and boracic ointments mixed in equal parts, or cold cream. The ointment should be evenly spread on linen rag, and kept in close contact with the affected skin. If dry chronic forms do not yield to similar treatment, tar ointment should be cautiously tried; but they sometimes require the use of a strong irritant, as a solution of caustic potash, or a fly-blister, before they heal. Such treatment should only be resorted to under medical advice.