This occurs where the folds of skin come in contact and rub on each other as between the thighs or beside the scrotum, sheath or mammæ in fat horses and other animals, on inner side of the elbow, between the digits in ruminants, on clipped heels in horses, and under harness. Irritant perspiration and sebaceous matter dried on, and mixed with more or less gritty or septic road dust contribute to it. Drying of clay and mud in the cleft of the frog, or in the interdigital space of ruminants is a common cause, also pricking with stubble.
Symptoms. These are most marked when the animal has been standing with the raw surfaces partially dried and adherent. After moving for some time, and when the surface has been moistened by the exudate there may be little lameness. Until then he moves hesitatingly and stiffly, with the legs abducted or in case of the hind ones straddling. With intertrigo of the pastern or frog, the horse stands on the toe or with the fetlock knuckled forward, and avoids as far as possible a full extension. The same is true of cattle with interdigital intertrigo.
The affected part is hot, perhaps swollen, red, damp and exceedingly tender. Under renewed work, lameness disappears, but becomes worse on standing, and an extensive exudation may occur subcutaneously. If this becomes infected it may result in severe and even destructive lesions, but it usually remains simple and proves readily responsive to soothing and protective treatment. It is most amenable to treatment in dogs and meat producing animals of which no work is required. On the contrary the latter when travelled long distances on foot may suffer severely.
Treatment. First abate the cause. With castile soap wash from the affected part the dried accumulations of sweat, sebum, dust and other matters, remove clay from frog, interdigital space or heels. Rest until the congestion and tenderness subside. Drying applications in the form of dusting powders are usually best: zinc oxide, lycopodium, magnesia oxide, may be dusted in freely after the affected part has been thoroughly exposed and dried. In the absence of these use gloss starch, corn starch, farina or white bismuth. To one or other of these may be added a little alum, lead acetate or morphia. The addition of a layer of surgeons’ cotton is useful, if in a place where it will be retained. Of liquid applications the veterinarians white lotion (zinc sulphate and lead acetate, of each 1 oz. water 1 qt.) is one of the best, being at once sedative and astringent. It may be applied on cotton. Astringent preparations with glycerine are useful but glycerine has the serious drawback of attracting moisture and increasing the secretion when drying is desirable. Carron oil (equal parts of lime water and linseed oil) is most effective and free from this objection. Vaseline alone or medicated with zinc oxide, lead acetate, alum or tannic acid may be resorted to when dusting powders fail. Morphia and camphor have been added when itching is violent.
In intertrigo of the frog or interdigital space the danger of infection from the floor or road is so great that the demand for antisepsis must overcome other considerations. Calomel freely applied to the surface, previously cleansed and dried, is most successful. It may be bound in place by a pledget of cotton and bandage. In other cases alum 5 parts, copper sulphate 1 part, or carbolic acid and tar may be bound to the part.
ERYTHEMA CALORICUM: SOLAR ERYTHEMA.
WHITE FACE AND FOOT DISEASE IN HORSES.
England to Africa, on white skins, especially of face. Symptoms: local congestion, swelling, itching, desquamation, during extreme heat: in worst cases fever, dullness, inappetence, costiveness, diarrhœa, head constantly moving, rubbing, vesicles, pustules, excoriations, cracks, fissures, septic ulcers in nose and mouth, submaxillary and pharyngeal swellings, recovery with dermal thickening and tenderness. Diagnosed from petechial fever by the itching, and the absence of petechiæ. Prevention: breed solid dark colors, avoid white skinned in hot climates or work in shade, away from hot winds; sunshade; avoid friction and wetting in sunshine. Treatment: shade, astringents, cool irrigation, vaseline, zinc ointment, lamp black, antiseptics. Tie so as to prevent rubbing.
This has been observed in different latitudes from the cool climate of Great Britain, to the burning suns of Africa, though it reaches its highest intensity in the hotter regions. The parts to suffer are those that are devoid of pigment, as the white star, snip or blaze on the face, the white feet or legs, the white areas in the piebald, and the whole surface in the albino. The white face, however, suffers more than the white legs, apparently because of its more constant exposure, the absence of shadow from the trunk, and the delicacy of the skin and fineness and thinness of the hair.
Symptoms. In slight cases there may be no constitutional disorder, only redness, itching, swelling and subsequent desquamation of epidermis on the white portion of the skin, which may prove persistent so long as hot weather lasts and recover on the advent of cold.
The more violent cases seen in warmer climes, may be heralded by febrile reaction, dullness, prostration, inappetence, constipation and sometimes diarrhœa. The head may be kept in constant movement, the itchy white parts being rubbed on any object within reach, and the limbs are stretched, the front ones forward and the hind backward, with a tendency to rub them with the nose or foot. The skin at first red, becomes later swollen, covered with vesicles which pass into pustules, burst and discharge. Meanwhile the subcutaneous connective tissue is infiltrated and gravitates toward the lowest parts, causing extensive submaxillary swellings and stocking of the limbs. In its worst forms it may go on to necrosis and sloughing, but more commonly the affected part becomes raw, excoriated, cracked and fissured. Sometimes the pituita or even the buccal membrane becomes involved, with muco-purulent discharge. In other cases the absorption of septic products causes inflammation and swelling of the submaxillary or pharyngeal lymph glands. Under favorable conditions, the secretions dry, the sores heal and the exudate is in great part absorbed, but there usually remains some thickening of the affected parts and a diminished vitality of the skin, which renders it morbidly sensitive to sources of irritation.