Form of white face disease, with irritating ingesta, buckwheat, etc.,
occurs from dried products, no insects; growing potatoes; sunshine;
idiosyncrasy. Symptoms: as in white face disease: in winter itching
and rubbing: in summer may go on to nervous symptoms. Treatment: stop
feeding buckwheat. Give laxative and diuretics. Local treatment as in
white face disease.
This may be held to be but a form of the last named affection, in which,
however, certain irritating ingesta (buckwheat, maize, wheat), are
essential factors in addition to the white skin and strong sunshine. It
is seen only on white skins or the white portions of parti-colored
skins, while the blacks, browns and other colors usually escape. Black
breeds of hogs (Essex) escape under the same feeding and exposure, as do
solid colored horses of the darker shades. Of the different food
factors, buckwheat (Polygonum fagopyrum, persicare, etc.), is the most
to be feared, and the poison seems to be inherent in all the products
(green vegetable, dry seeds, bran and straw) and is not destroyed by
cooking. Buckwheat cakes sometime produce erythema in man. This excludes
the idea of the transfer of a living cryptogam to the skin, though not
the theory of pathogenic products of the fungi. The invoking of bee
stings and the bites of insects, which are strongly attracted to the
buckwheat, is untenable because the affection occurs from the dried
seeds, bran and straw, and has been known to break out weeks after the
buckwheat was withdrawn from the ration.
In addition to buckwheat, maize and even wheat when liberally fed have
been known to cause erythema. Hemminger records a similar outbreak in
horses working among growing potatoes.
In addition to the food, clear sunshine is essential and an individual
idiosyncrasy. All animals, though equally exposed are not equally
attacked.
_Symptoms._ These do not differ materially from those of the white face
and foot disease already described. There are intense redness and
tumefaction of the white skin or the white portions, showing prominently
in the delicate parts (ears, eyelids, lips), with violent itching,
rubbing and sometimes vesicles with yellowish contents, followed by
sores and scabs. In the winter season there may be itching and rubbing
only. In summer it may become erysipelatoid and extend to the mucosæ, of
the respiratory and digestive organs, with hyperthermia, nervous
excitement, vertigo, turning in a circle and even spasms and
convulsions.
_Treatment._ This is essentially the same as for the white face and foot
disease with this additional that the buckwheat or other offensive
ingredient must be withdrawn from the ration, and what remains in the
bowels must be expelled by saline or other laxative. Cooling diuretics
must follow to eliminate irritant matters that may have been absorbed.