From impetiginous eczema it is diagnosed by its contagious and inoculable properties, by the absence of the early falling of the hair from the circumscribed rounded nodules, and by the absence or moderate character of the pruritus which is usually intense in the eczema.
The eruption of urticaria appears much more suddenly, shows no tendency to form vesicles nor pustules, is not inoculable, and subsides often as suddenly as it appeared when the irritant food materials have been expelled from the alimentary canal.
From acute farcy it is distinguished by the moderate degree of the implication of the lymph vessels and glands, by the white creamy nature of the contents of the pustules, as compared with the glairy, oily nature of the farcy discharge, by the absence of coincident nasal ulcers, submaxillary nodular swellings or other lesions of glanders, by its short course and tendency to spontaneous early recovery, and by the absence of reaction under the mallein test.
In all cases the known prevalence of the contagious pustular dermatitis in the locality, or the introduction of strange horses which exhibit sequelæ of the lesions will assist greatly in the diagnosis.
Prevention. If animals are introduced from an infected or unknown locality they should be kept apart from others for two weeks. In a stable where it has already appeared the diseased and healthy should be carefully separated and the skins of those as yet unaffected may be washed with a solution of mercuric chloride (1 ∶ 1000) or creolin (1 ∶ 100). The walls of the stable should be whitewashed, and all stable utensils disinfected in boiling water or one of the above named antiseptics. The harness demands particular attention.
Treatment. This is essentially germicide. After a soapy wash, any one of the usual disinfectants may be used: aluminum acetate, (1 ∶ 15), mercuric chloride (1 ∶ 1000), carbolic acid (1 ∶ 50), creolin (1 ∶ 50), copper sulphate (1 ∶ 50), etc. Lead acetate 2 parts, alum 1 part and water 50 parts, has been found to be effective.
PEMPHIGUS IN HORSE, OX, PIG AND DOG.
On rare occasions the horse or ox is attacked with a skin eruption, attended with the formation of bullæ or blisters, from the size of a hazel nut to a hen’s egg, or larger. It is sometimes shown sporadically and at others appears at once in a large number of animals in the same herd. The causes are obscure, yet the enzootic appearance of the affection is suggestive of a common factor entering probably by the food. Loiset and Seaman have recorded enzootic outbreaks in cattle and Dieckerhoff in the horse.
Symptoms are cutaneous congestion with the formation of swellings like a walnut, but exceptionally as large as the fist, on the head, neck and thorax, which in 2 to 4 days form a large central vesicle, with yellowish serous contents. Cases in the ox (Loiset, Seaman) had a similar eruption on the loins, quarters and hind limbs, some of the swellings attaining the size of a hen’s egg, and with similar contents. Later these ruptured, crusted over and healed, with, for a time, a smooth glistening surface. Winkler records cases in swine and Schneidemühl in dogs, but the condition is rare in both animals.
Treatment. To a nutritious, non-stimulating and easily digestible diet, may be added a course of arsenic and, in low condition, of bitters. Locally dusting powders of zinc oxide, boric acid, starch and lysol. Should the exudate form these into hard cakes, they may be replaced by carbolized oil or, better, a 5 per cent. mixture of ichthyol in vaseline.