Chronic Progressive Lymphoedema

This condition was initially thought to be a therapy resistant form of pastern dermatitis (please see under 'Conditions' Pastern Dermatitis) affecting Shire and Clydesdale horses. However, research at the University of California, Davis, School of Veterinary Medicine, pointed to the typical infections and infestations as being secondary to an underlying, then undiscovered cause affecting the vascular and immune systems.

Further research eventually identified this as a lymphoedema and because of its nature, It has been named Chronic Progressive Lymphedema.

CPL has now been identified in Shires, Clydesdales, Belgian Draft horses and recently Gypsy Cobs, who have the first two breeds in their heritage. Initially it was thought to be a rare condition but has now been found in numerous horses within the affected breeds. The disease is congenital i.e. a primary lymphoedema, and may be hereditary, and it is conceivable that other horses with the affected breeds in their background may be vulnerable.

Researchers at UC Davis and Ghent University, Belgium, have been looking for a cause for the condition which could be identified before clinical signs appear. Their findings indicate that in affected horses' bodies, elastic fibres which are essential to the function of the lymphatic system (and which are damaged by lymphoedema) are abnormal.

CPL starts at an early age and progresses through the horses life, often ending in disfigurement and disability in the legs, comparable to the most severe stage of human lymphoedema. Infections such as lymphangitis play a significant role in the development of other forms of equine lymphoedema, however this does not appear to be necessary for the development of CPL.

Because CPL affects horses with feather, early signs such as skin thickening, crusting and oedema causing folds below the fetlock are often overlooked. The reduced immunity makes these horses especially vulnerable to secondary bacterial and fungal infections and infestation by mites, but treatment for these is often of limited success. (Picture: early folds, clipped leg, Gypsy Cob)(M Way).

With time the oedemic tissue becomes fibrotic and develops further folds and very hard nodules which can become as large as golf or tennis balls, extending around the pastern and up the affected leg. The swollen skin may crack and a protein rich fluid called 'lymphorrhea' seep out, which is caustic and very attractive to bacteria.

A vicious cycle develops: the damage caused by lymphoedema, plus the environment created by heavy feather, provide perfect conditions for bacterial infections and mite infestations, which further damage and imflame the vulnerable tissues.

Failure of the immune system to handle infection at this stage of lymphoedema frequently results in infections such as lymphangitis which if not treated successfully can spread and become life threatening.

(Picture: advanced chronic progressive lymphoedema)(fotocloet)

We have just completed a small trial at UCDavis Centre for Equine Health into the successful use of EMLD to manage Chronic Progressive Lymphoedema, and will be updating this and the website below with the results.

For further information: www.vetmed.ucdavis.edu/elephantitis/about.html