Eczema is the most common disease occurring in the horse, typical of the catarrhal condition of the skin. It consists, in the first instance, of inflammation of the superficial layers of the true skin, with an eruption of small papules, or vesicles, which sooner or later break and discharge a watery fluid of a somewhat adhesive character, as shown by the gluing of the hair in tufts. Later, small scabs or crusts appear at the seat of eruption, and are frequently rubbed off by the animal trying to relieve the itching, leaving raw surfaces beneath.

Fig. 265. - Urticaria.

Eczema presents itself under several forms. When the attack is mild, without any symptoms of constitutional derangement, the disease is termed eczema simplex. In more severe attacks, when the inflammation of the skin is more pronounced and the surface is swollen and tinged with red, the term eczema rubrum is used. In the most severe form of the disease the eruption becomes pustular, when the small vesicles are filled with "matter" instead of watery fluid. A fourth form of the disease is characterized by the cuticle of the skin being thrown off from the affected part in bran-like scales. This is described as squamous eczema, and has a great tendency to become chronic. Eczema may occur in different parts of the body, but it is perhaps most common in the upper part of the neck and over the quarters. The symptoms of the disease, from first to last, vary according to the stage. Congestion is observable at the commencement, indicated in light - skinned animals by a redness of the surface (erythema). This is followed by an eruption of pimples, next vesicles or blisters form and break, and discharge their contents. Should the inflammation be acute, the discharge becomes purulent. From the first there is some irritation and itching, which may induce the animal to rub or bite the diseased parts within reach. Eczema may be distinguished from other skin affections, for being a distinctly catarrhal disorder it is always associated with a discharge of a more or less sticky fluid, and is therefore described as a "moist disease".

Fig. 266. - Eczema.

Treatment must be adapted to the stage of the disorder. In the simple forms, soothing treatment is recommended; as the disease advances to the pustular stage, tonics and astringents are prescribed, and in the last stage stimulants are advocated. In the simple form, an alkaline lotion with a little glycerine and a small quantity of tincture of opium will relieve the irritation; or in place of the lotion, flour may be sprinkled over the moist parts. In the final stage, when crusts are being formed, a ten-per-cent solution of carbolic acid may be employed, and when the surface becomes dry and covered with scurf, the ointment of the oxide of zinc will be beneficial. Throughout the disease saline laxatives may be administered when necessary, and in the latter stages tonics, such as mineral acids and iron, and in some cases arsenic, will be indicated. Arsenic is most conveniently administered in the form of Fowler's solution, in doses of one ounce to an ounce and a half, which may be sprinkled on the food night and morning, or mixed with the drinking water.