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.