White skins or white patches on the skin are especially liable to suffer as in cases of fagopyrism and “grease”. The action of the solar rays in summer must therefore be accepted as a concurrent cause.
Symptoms. The first symptoms are usually those of cutaneous congestion or inflammation. Redness, swelling, pitting on pressure, or tension, are accompanied or followed by vesicles, chaps or erosions. The margins of the sores become thick and irregular, often undermined, and they gradually increase by breaking down of tissue in their depth or on their margin. In other cases patches of skin dry or wither up, either in superficial layer or throughout its entire thickness, and these dried extra vascular sloughs are gradually detached by granulation beneath. The surrounding tumefaction is always extensive and the sores may expose the deep seated structures—tendons, ligaments, fascia, bones, joints—causing widespread destruction.
Treatment. If the disease is due to capillary occlusion of nervous origin, compresses with camphorated spirit, followed by camphorated vaseline may be of advantage. If otherwise, antiseptics will be in order: carbolated vaseline, salicylic acid cream, iodoformed vaseline, a weak iodine ointment, creolin, or lysol in water, tar water. When the dead tissues are partially separated the detachment may be hastened with knife or scissors and the sores treated like a septic sore.
CUTANEOUS HYPERTROPHY. ELEPHANTIASIS. PACHYDERMIA.
Chronic thickening of skin and lymph plexuses, horse hind limb after eczema, grease, glanders, ox neck and head, knees, shoulder. Calcification. Treatment: laxatives, diuretics, exercise, elastic bandage, friction, astringents, iodine.
Chronic thickening of the skin is most commonly seen in horses as a sequel of lymphangitis in the hind limb, the engorgment of the lymph plexus and thickening of its walls being associated with a general productive inflammation and thickening of the derma until the fetlock may be thirty inches or more in diameter. It may follow eczema, grease or chronic glanders. In cattle a productive dermatitis in the region of the head and neck, has led in the experience of the author to a similar distention of the lymph vessels and morbid thickening of the skin. The pads and calluses which form on the knees of the camel and on other parts subject to friction, furnish examples of hypertrophy of another kind. Again the thick dense cutaneous plates on the shoulders of the old boar may serve to illustrate a physiological hypertrophy. The writer has seen thickening of the skin in the seat of an incision made in spaying the pig and the deposition of earthy salts so as to form a distinct calcification.
Treatment is very unsatisfactory, yet something may be done by laxatives, diuretics, regular exercise, an evenly applied elastic bandage when in the stable, massage and the use of astringent and dilute iodine ointments. It is much more important to prevent the lesion by cutting short the morbid condition on which it depends. When developed, attention is usually given to prevent its advancement and to utilize the animal at slow work.
ICHTHYOSIS. FISH-SKIN DISEASE.
This consists in a scaly formation of the epidermis which is also formed in excess, and is supposed to be dependent on disordered trophic innervation. In new born calves suffering in this way Van Stettin found an excess of phosphate of lime in the epidermis. The calves usually die in a few days.