C.P.L

A condition characterized by progressive swelling, hyperkeratosis and fibrosis of distal limbs has been recognized in Shires, Clydesdales and Belgian Draft horses. This chronic progressive disease starts at an early age, progresses throughout the life of the horse and often ends in disfigurement and disability of the limbs which inevitably leads to the horse’s premature death. The pathologic changes and clinical signs closely resemble a condition known in humans as chronic lymphedema or elephantiasis nostras verrucosa. The lower leg swelling is caused by abnormal functioning of the lymphatic system in the skin, which results in chronic lymphedema (swelling), fibrosis, a compromised immune system and subsequent secondary infections of the skin.

CHRONIC PROGRESSIVE SWELLING, HYPERKERATOSIS AND FIBROSIS OF DISTAL LIMBS IN CLYDESDALES, SHIRES AND BELGIANS SUGGESTIVE OF CHRONIC LYMPHEDEMA.

Based on preliminary research, it appears that a similar pathogenic mechanism is involved in the disease that affects these specific draft horse breeds. The clinical signs of this disease are highly variable. The earliest lesions are characterized by skin thickening and crusting; both are often visible only after clipping the long feathering. Secondary infections develop very easily in these horse’s legs and usually consist of either chorioptic mange or bacterial infections. Both dark and white skin on the lower legs are equally affected. These lesions are consistent with pastern dermatitis, a a process also seen in other breeds. In Shires, Clydesdales and Belgians however, these lesions do not respond well to therapy. As the condition becomes more chronic, the lower leg enlargement becomes permanent and the swelling is firm on palpation. More thick skin folds and large, poorly defined, firm nodules develop. The nodules may become quite large and often are described as “golf ball” or even “baseball” in size. Both skin folds and nodules first develop in the back of the pastern area. With progression, they may extend and encircle the entire lower leg. The nodules become a mechanical problem because they interfere with free movement and frequently are injured during exercise. This disease often progresses to include massive secondary infections that produce copious amounts of foul-smelling exudates, generalized illness, debilitation and even death.