The symptoms do not appear until after two or three weeks’ feeding on the potato pulp. Then the animals walk stiffly, rise with difficulty, and display redness, swelling and sensitiveness of the limbs. When the œdematous infiltration and reddening have become distinctly marked there appear, not only between the claws, as in foot-and-mouth disease, but over the entire limb and principally near the folds of skin about the joints, numerous closely-packed small papules, which in one or two days become transformed into vesicles through exudation below the epidermis.
This marks the eczematous phase properly so called. The vesicles then become ruptured, the exuded matter glues the hairs together, dries, and forms crusts, which have a peculiar and distinctive odour.
The disease may extend towards the hocks, the knees, the stifle, the armpit, etc. In the folds of skin surrounding the joints deep cracks form, and sometimes become secondarily infected, thus leading to the development of lymphangitis.
General symptoms, such as fever, loss of appetite and constipation, always follow; they are afterwards succeeded by diarrhœa and progressive weakness, ending in death.
The disease is easily curable if seen in its earlier stages, but after all signs of the first attack have disappeared, the condition may return five or six times in a year if potato pulp is again given. Recovery is always very difficult in aged or enfeebled patients.
The mortality varies greatly; formerly it was as high as 20 per cent., but at the present time it is much lower.
Diagnosis. Provided the history of the case is borne in mind, the diagnosis is always easy.
The prognosis is not grave if the disease is treated early.
Treatment. This consists first of all in altering the diet and reducing the quantity of potato pulp, or, better still, in discontinuing it entirely. The food should consist of good hay, bran, oatmeal gruel, pollard, etc. Internally, diuretics are given to assist in the elimination of the toxic products.
This treatment arrests the course of the disease. Suitable local treatment will remove the existing lesions. It is precisely similar in character to that of acute eczema, but it must be borne in mind that it can only prove effective if the primary cause be removed.