Part 90

=Chronic Eczema of the Back in Dogs.= =Rodent Eczema= is a disease of fat, old, voracious dogs. It appears in circumscribed spots and patches on the back, loins, croup or tail and is marked by inveterate itching, congestion and thickening of the skin, cracking of its surface, bristling, breaking and shedding of the hair, exudation from the surface and its dessication in the form of crusts. These crusts may be black from contamination with dust or blood, and the affected surface is more or less fœtid. The skin may be puckered into irregular folds, thick and inelastic. Not infrequently the malady may remain dormant for some time, only to break out again and again with renewed energy. It is very obstinate and intractable.

=Chronic Eczema of the Elbow and Hock in Dogs.= This attacks the summit of the olecranon or calcis and is manifestly connected with compression and friction on these parts when lying down, and perhaps with foul and irritating matters on the ground. This need not be looked on as the sole cause but only as the occasion for the localization of a predisposition which was already present in the general system. The skin becomes red, thickened and indurated, the epidermis undergoing hypertrophy to form a callus, in which a few cracks and sores may form, giving rise to a discharge which encrusts the surface and adds to the thickness and induration. The affection is very inveterate.

=Chronic Dry Eczema of Head, Ears, Neck and Limbs in Dogs.= The dry eczema of the head, neck and limbs is characterized by its slow progress and its restriction in the majority of cases to one or more of these parts. The small affected patches, have some thickening and folding of the skin, which is usually dry, scaly and largely divested of hair. Itching is moderate only, and the hairs are shed less rapidly than in the encrusted forms.

Treatment. When there has been a fresh irruption it may be requisite to treat chronic eczema, for a time, after the manner of the acute, so as to avoid any tendency to aggravation of the already existing irritation. A careful regulation of the diet is as essential in the chronic forms as in the acute and in the inveterate types, especially those of a squamous character, alteratives like arsenic are often of value. In the acute stage or during a recrudescence the mild dusting powders (starch, zinc oxide, lycopodium, magnesia bicarbonate, bismuth oxide, thiol) may be applied, or bland unguents (zinc, benzoated zinc, lead, vaseline, glycerine, spermaceti and almond oil, paraffin, wax), or sedative lotions (lead, opiate, thymol, thiol, carbolic acid).

In the more advanced and moist forms astringents and stimulants may be adopted: silver nitrate (2 ∶ 100), applied with soft cotton, mercuric chloride (1 ∶ 1000), or black wash (calomel 1 : lime water 60) care being taken to use a close wire muzzle to prevent licking. Copper sulphate (1 ∶ 100) is at times useful, and boric acid, and tannin may be tried. Iodoform 1 part and tannic acid 5 has a good effect in many cases.

For the dry and scaly forms, and indeed for many of the others, as well, the more stimulating ointments and liniments are called for. Cadeac recommends oil of cade, tinctures of cantharides, or a tar liniment made with alcohol, as a supersedent to produce an active inflammation and displace the unhealthy eczematous one. The agent is rubbed upon the skin and the resulting scabs are left for a week when it is washed off with tepid water and the skin is found healthy or greatly improved. As a rule a second dressing of the tar is then applied. Müller strongly recommends Hebra’s treatment with green soap and alcohol (2 ∶ 1) to be rubbed on the affected surface and washed off the following day when all scales and crusts will come off with little trouble. He follows with zinc oxide or lotions of mercuric chloride or silver nitrate. Friedberger and Fröhner use cresol 2 parts, green soap 2 parts, alcohol 1 part; also creosote in alcohol (1:10) or in paraffin (1 ∶ 10). Zuill looks upon sulphur iodide as virtually a specific: sulphur iodide 1 part, sublimed sulphur 7 parts, cod liver oil 7 parts. This is applied once and repeated at the end of ten days, if necessary. Application is made to the whole skin healthy and diseased alike, and rarely requires to be repeated.

Ichthyol is commended by Müller in cases which show great cutaneous thickening with cracks and fissures. It may be made with water (1:5) or in glycerine or lanolin of the same strength. Müller combines it with lime water and olive oil and applies it daily.

Other agents in use are salicylic acid in olive oil (1:3): chrysarobin in paraffin ointment (1:4): naphthalin or naphthol (1:10): resorcin in water (2:100)

LICHEN. HEAT PAPULES. PRICKLY HEAT.

Horses, cattle, sheep and dogs suffer in hot season or hot stables. Nervous temperament. Delicate skin. Over-driving. Heating foods. Cold water when heated. Unwholesome food. Indigestion. Chronic affections of stomach, liver, kidneys, etc. Symptoms: Clusters of small papules on neck, back, croup, or thighs, crest, tail, exudate concretes, lifts hairs from follicles, depilation in round spots, or patches, abrasions, ulceration, corrugated skin. Diagnosis; sudden eruption, its isolation, subsidence on the coming of cold weather, and re-appearance with the hot, intense itching. Treatment: As in eczema. Protect against friction, give shade, and spray with cold water.

Under this name has been described a papular eruption occurring in horses, cattle, sheep and dogs in the hot season, but also occasionally, in winter, in hot, confined stables.

It is seen especially on the neck, back, croup and thighs, is common in fine bred horses with delicate skins, and nervous temperament, and is pre-eminently a disease of hot weather. Over-driving, heating food, a drink of cold water when heated or indigestion connected with unsuitable food may be the occasion of its irruption or tend to perpetuate it. In the same way different chronic affections of the stomach, liver, kidneys or other organs may be causative factors.

Symptoms. The affection usually begins with a few minute papules, isolated or in clusters, which dry up into scales or crusts. These are mostly situated at the roots of the mane or tail or on the sides of the neck, withers or trunk, and as a rule produce a pruritus, resembling that of scabies in its intensity. When the exudate agglutinates a tuft of hair, enclosing it in a dense crust, the hairs may be lifted from their follicles and thus small, round spots of depilation appear. If recovery ensues and new hair starts, it differs in color from the old and gives a dappled appearance to the skin. In many cases, however, the points of eruption and encrustation become confluent and an extensive area of bareness, with more or less abrasion, and even ulceration may be formed.

Megnin mentions two cases and the author can adduce another in which the eruption appeared in vertical lines, so that the skin of the trunk was raised in a series of elevated lines or ridges, running transversely to the body, like the stripes of a zebra. In the author’s case the skin seemed to be thrown into a series of folds to the production of which the cutaneous muscle evidently took part. The itching was doubtless the immediate cause.

Diagnosis is based largely on the suddenness of the eruption; on its limitation to a given area instead of spreading from the primary seat of invasion as in acariasis; on the fact that it is usually confined to a single animal and has not spread with the use of the same brush, comb and rubber; and on the absence of acari and vegetable parasites from the affected parts. The absence of chicken roosts or manure is another valuable indication.

Prognosis. Appearing in spring or early summer, the disease is liable to persist until the advent of cold weather in fall, and even after a winter’s intermission there is a strong tendency to its re-appearance on the following spring or summer. The intolerable itching interferes seriously with docility and steadiness in harness, and the loss of hair renders the subject very unsightly, and as a family or driving horse practically useless.

Treatment. As in cases of eczema the general and special causes should be corrected by hygienic and general medicinal measures, laxatives, diuretics, antacids, tonics, and in the advanced stages, alteratives coming in as important factors. (See under acute eczema). Great care should be taken to prevent irritation by pressure of the harness, and shade and daily cold spraying may be availed of.

PITYRIASIS: SQUAMOUS SKIN DISEASE: HORSE.

Dry, scaly, or powdery affection. Causes: Fine, thin, dry skin with little hair, race, Arab, Barb, racer, trotter, nervous temperament, age, dry summer heat, dry winter cold, foul skin, caustic soaps, ingestion of salt, iodides, bromides, etc., derangement of internal organs bacteria or cryptogams. Symptoms: scurfy patches, general or circumscribed, where little hair is, where harness rubs, depilation of ears, crest, tail, shoulder, back. Diagnosis, from eczema by lack of pruritus, of rapid extension, of thickening of the skin, from acariasis by absence of acarus. Treatment: correct disorder of stomach, liver, or kidneys: green, succulent or nutritive food; alkalies; arsenic; tonics; locally potash soaps, ointments of tar, birch oil, creolin, creosote, naphthalin, lysol, mercury, iodine, salicylic acid, zinc oxide.

This is a skin disease characterized by excessive production of epidermic scales, and depilation without any attendant elevation of the skin. The desquamation may be of fine scales like wheat bran, or of a fine dust like flour.

Causes. The disease is especially characteristic of animals in which the skin is naturally fine, thin and dry and covered sparsely with hair. It is therefore more common in the Arabian, Barb, English racer, American trotter and other breeds of a nervous organization than in the heavier draught breeds. Old horses in which the skin is drier and the hair thinner are more subject to it than the young. Again it has been especially noticed in the heats of summer with thin coat and a withering action of radiant heat on the skin, and less frequently in winter when the blood is driven from the surface by cold. Much also depends at times on the lack of grooming, on the accumulation of dust and dried up secretions about the roots of the hair, and on washing with caustic irritant soaps especially in long-haired regions. It has even been claimed that the ingestion of salt, potassium iodide, or bromide, etc., contributes to the affection. There is undoubtedly a certain individual predisposition to the disease, shown as already stated in certain breeds, but also inherent in particular families and even animals, and associated not only with the character of the skin, but also probably with variations in the activities and products of various internal organs. In man pityriasis versicolor is associated with a specific fungus, and in the horse Megnin has described cases in which the surface of the skin and especially the hair follicles show a mass of epidermic cells mingled with mycelium and an abundance of spores.

Symptoms. The scurfy product and depilation may be found in patches scattered indiscriminately over the body (generalized), or confined to particular regions (circumscribed) as to the head, ear, crest, tail, or the parts that receive the friction of the harness. It may commence as a dry, rigid, state of the skin under the headstall with loss of hair and the excess of dandruff. From this or from another point the extension takes place slowly and with comparatively little irritation or itching. The hair is pulled out with great ease, and from its spontaneous evulsion, more or less baldness appears progressing slowly from the original centres of the disease. It may leave the whole crest divested of the mane, or the tail of its hairs (rat tail), or the ears may become bare and scurfy. Again the parts subject to friction like the back of the ears, the crest, in front of the shoulder, or the seat of the saddle may be the main seats of depilation and baldness.

It is to be distinguished from dry eczema mainly by its tendency to spread over a larger area in place of confining itself to circumscribed patches, and more particularly by the absence of the marked thickness and rigidity of the skin which characterize eczema. From acariasis it is distinguished by the lack of the intense itching, of the tendency to more or less moist exudation and above all by the absence of the acari.

Treatment. It is well to correct any disorder of any of the internal organs, notably of the stomach, liver or kidneys, and to encourage a free circulation in and secretion from the skin. To fill the latter indication green food, ensilage, roots, sloppy mashes of bran, oilcake and the like may be given. Also bicarbonates of soda or potash or other alkaline diuretics, and in certain obstinate cases a course of arsenic. The alkalies tend to eliminate offensive and irritant matters and to lessen the irritation in the skin. A course of tonics is often valuable.

Locally Cadeac recommends potash soaps rubbed well into the affected parts. If this should fail some of the stimulant ointments as of tar, oil of tar, oil of white birch, oil of cade, creoline, creosote, lysol, naphthalin, may be tried. Megnin strongly recommends a combination of ointment of biniodide of mercury, 1 part, to mercurial ointment 3 parts. Others advocate salicylic acid (10 to 20%) mixed with Lassar paste which is compounded of 1 part each of zinc oxide and starch in 4 parts vaseline.

PITYRIASIS IN CATTLE.

On neck and dewlap; Causes: anæmia, debility, spoiled food, starvation, constitutional predisposition. Symptoms: shedding hair and scales without skin thickening, or itching. Treatment: green soap, tar, creolin, lysol, naphthalin, etc. Alkaline lotions: generally nutritive, succulent food, bitters, iron, arsenic, etc.

This is noticed especially on the neck and dewlap in connection with anæmia, low condition, unsuitable, innutritious and spoiled fodder and a constitutional predisposition. It has the same general characters as in the horse, an excessive production of dandruff or dry scales without any marked change in the thickness of the skin or in its circulation. Treatment consists in the application of green soap, pure or medicated, with tar, creolin, lysol, or other empyreumatic product. Lotions of carbonate or bicarbonate of potash are often effective. Any disorder of digestion, or of the urinary or hepatic functions, or of general nutrition should be corrected, and in most cases, a course of bitters, with iron and arsenic is desirable. A good, indoor hygiene or a run on succulent grass in the open air may be resorted to with benefit.