In dogs this affection attacks especially the head, neck and back of pet and house dogs gorged with dainties, and particularly in those that are already becoming aged. The affected parts are covered with a floury or branlike product lying upon a dry surface usually devoid of irritation or congestion, though it may be distinctly congested and reddened, and even the seat of pruritus. The affection is usually confined to limited areas, more or less destitute of hair, and without showing a disposition to active extension. In the cat, however, it may affect the whole dorsal aspect of the body, being associated with extreme electrical susceptibility, so that on being stroked the hair at once collects in tufts, crackles, and in the darkness sparkles, and the animal at first fawning on the hand, will fly at and scratch it after a few strokes. The scaly product is excessive and drops off abundantly when handled, without, however, leaving thin or bare patches.
Treatment is mainly in the line of a simpler and more natural diet, the avoidance of sugar and cake, the correction of disorders of the digestion, or of the hepatic or urinary functions, the exhibition of an occasional laxative, and of alteratives, especially Fowler’s solution.
Locally, alkaline lotions, carbonate or bicarbonate of soda or potash, borax, sulphide of potassium and iodide of sulphur are often useful. A moderately strong solution of common salt with glycerine in water is an useful alternate, and a warm saline or bran bath may soften the skin and modify its nutrition.
CONTAGIOUS PUSTULAR DERMATITIS IN THE HORSE. ACNE.
History. Cause: bacillus. Symptoms; incubation 6 to 15 days, skin tenderness, heat, swelling like peas, hazel nuts, vesicles, pustules, exudation, concretions among hairs, depilation, healing in 15 days. Leaves white spots with lighter hair. Extension by grooming: general eruption: subcutaneous swelling, sloughs, delayed healing. Lymphangitis. Diagnosis: from chaps and bruises, from horse pox, from impetiginous eczema, from urticaria, from farcy. Prevention, quarantine new horses, separate diseased, disinfect skins of the unaffected, disinfect stables and harness. Treatment: soapy wash: germicide lotions.
This has been largely described as an imported disease thus on the European continent it is the English variola, and in England the Canadian contagious pustular affection. Yet the first authentic account dates back to 1841–2 when Goux found it attacking an entire squadron of the French army in a fortnight. Axe described it in England in imported Canadian horses in 1877, and Weber observed it in the same year on the continent, where it was attributed to imported English horses. In 1883 it was noted by Schindelka, in 1884 Siedamgrotzky inoculated it from the horse on two rabbits and two Guinea pigs, and to horse and goat. The rodents developed a “malignant œdema” at the point of inoculation and died in six days. Grawitz and Dieckerhoff cultivated the bacillus on ox or horse serum and found it 2μ in length, dividing by segmentation into round or ovoid refractive spores, which may remain connected as diplococci or short chains and which color deeply in fuchsin. It grows most rapidly at a temperature of 37° C., growth ceases at 17° C., and it is destroyed in half an hour at 80° to 90° C. Preserved, dry, it remained virulent for four weeks and produced the characteristic eruption when rubbed on the skin of the horse, ox, dog, sheep or rabbit. It proved fatal to all rodents, including white mice. The microbe is found abundantly in the pus and crusts and is easily shown when these are treated with potash. It produces no putrid fermentation.
Symptoms. When inoculated it had an incubation of six to fifteen days followed in mild cases by swelling heat and tenderness of the skin with collection of the hair in erect tufts. Next day there are rounded elevations like peas or hazel nuts, discrete or confluent on the swollen patches. These nodules, at first firm and resistant soon become soft in the center, forming vesicles and finally pustules, which burst in five or six hours and exude an abundant liquid which concretes in a thick amber colored mass. The hairs in the center of the resulting raw surface are easily detached leaving bare spots the size of a dime, with often times a slough attached in the center. When this is finally eliminated the surface gradually cicatrices and recovery may be complete in fifteen days. The skin remains long dappled from the partial discoloration of the epidermis in the seat of the pustules. The malady is local and hyperthermia is rarely seen. The submaxillary and pharyngeal lymph glands are usually swollen and indurated, but this disappears speedily after the subsidence of the eruption.
In certain cases the extent of the primary eruption is greater from the first, or it extends through reinfection by combs, brushes and rubbers used in grooming or by friction by the harness, the affected skin is hot, painful, congested and thickened throughout its entire substance, the pustules are much more numerous, often confluent, and may even implicate the subcutaneous connective tissue. The crusts formed on the sores may acquire a breadth of 1 inch to 1½ inch. Considerable abscesses may be formed and the lymph glands communicating with the affected part are hot and swollen. Even after the opening and discharge of the abscess, the base of the sore remains indurated and indolent, and centres of softening and caseation may appear so that healing is delayed for one or two months or more. In such cases extensive cicatrices remain after recovery. Lymphangitis is a common accompaniment with even abscess of the lymphatic glands.
Diagnosis. From chafing and bruising by the harness, this is easily recognized by its appearing also on other parts than those covered by the harness, by the development of the characteristic pustules, by its following a regular cycle of eruption and subsidence covering a definite period of usually 15 days, and by the indisposition to maintain itself indefinitely under the friction of the harness.
From horsepox it is distinguished by the habitual avoidance of the common seats of election of that disease (heels, lips, nostrils, buccal and nasal mucosæ, lips of the vulva), by the absence of hyperthermia, and by the comparative absence of the remarkable amber-like concretions which characterize horsepox in the lower limb.