Purpura hemorragica in a horse manifests with symptoms such as swelling of the head, legs and underbelly, and red spotting on the gums and other mucus membranes, notes the University of Minnesota. Serum may seep from a horse's skin, and in severe situations, a horse's skin may die and slough off, exposing the underlying tissue. Other symptoms include colic, lameness, weight loss, neurologic signs and laminitis.
Purpura hemorragia is caused by vasculitis, due to the horse's immune system having an inappropriate response, reports the University of Minnesota. In purpura hemorragica, the immune system damages blood vessel walls, making the blood vessels leak. This condition is often associated with a horse having previous bouts of strangles, and it may also be associated with bacterial or viral infections. Purpura hemorragica is not contagious.
To treat purpura hemorragica, a veterinarian must dampen the immune response and remove the underlying cause, states the University of Minnesota. Veterinarians typically recommend that a horse take a corticosteroid and antibiotics. Purpura hemorragica is difficult to prevent. Veterinarians may suggest not to readminster the strangles vaccine to horses who have experienced prior reactions to the vaccine.
In most cases of purpura hemorragica, the disease is mild and horses recover well, reports the University of Minnesota. In severe cases the horse may die or be euthanized.