Eczematous inflammation of the skin may occur in all domestic animals, but
it is most common in the dog. In the horse local eczema (scratches) is
common.

The most frequent _cause_ is external irritation. Accumulations of filth on
the skin and continual wetting of the part are common causes. Mechanical
causes are rubbing, pressure, the action of the sun's rays and chemical
irritants. Internal causes, such as catarrhal diseases of the stomach and
weakness and emaciation from disease, may act as direct or predisposing
causes. Tender-skinned animals seem to be predisposed to the disease.

_The symptoms_ vary in the different species of animals. In the horse the
thin skin posterior to the fetlock and knee, in front of the hock and on
the under side of the body is most commonly inflamed. Moisture and dirt
seem to be the most common causes. Eczema may involve the skin covered by
the mane and tail in animals that are not properly groomed and inclined to
rub or scratch. Cattle may suffer from eczematous inflammations in the
region of the forehead, back of neck and base of tail. A very common form
of the disease involves the space between the toes. Sheep frequently suffer
from inflammation of the skin over the fetlock region. The skin of animals
having long fleeces, or heavy coats of hair that become wet at a time when
there is no opportunity to dry out quickly, may become inflamed. Dogs are
commonly affected by the acute and chronic forms of eczema. Eczema of swine
is limited mostly to young hogs. It is rather rare, excepting in hogs that
are pasturing on certain kinds of clover and rape, or on muck lands.

The inflammation is accompanied by a marked tenderness and itching, and the
animal licks and scratches the part. This increases the extent of the skin
lesions. The skin appears moist, later dirty, scabby and thickened. Cracks
and pustules may form. Gangrene and sloughing of the skin may occur.