by Carol Gosselin

What is Chronic Progressive Lymphedema?  
Chronic Progressive Lymphedema (CPL) is a condition caused by the abnormal functioning of the lymphatic system in the skin, which results in chronic lymphedema (swelling). 

CPL is characterized by progressive swelling, hyperkeratosis (abnormal thickening of the outer layer of the skin) and fibrosis of distal limbs (the thickening and scarring of connective tissue of the distal limbs). The distal limb bones are the foundation of the equine lower leg; the distal limb is everything below the knee and the hock. It was originally thought to be a rare disease, but now is quite common in heavily feathered horses.

What causes CPL?
CPL appears to be caused by defective elastin, the protein important to the structure and activity of the lymphatic system. CPL is thought to be hereditary. Some horses suffer more than others and it’s possible for one horse with CPL to reach a good age with relatively little visible damage, and for another much younger one to quickly develop fibrosis. As with all lymphedemas, paying scrupulous attention to skin health and condition can make a big difference, especially if this starts at an early age. Research into CPL is ongoing.

What breed(s) of horse is CPL found in?
CPL is most noted in large draft breeds with heavily feathered lower extremities such as Shires, Clydesdales and Belgian horses. It has been also been found in many Gypsy Cobs and most recently in Friesians.

Early on, the disease may appear to be what often is referred to as a therapy-resistant pastern dermatitis, "scratches" or "mud fever," but over time, in addition to skin lesions typical for scratches, affected horses have vascular and lymphatic-vessel changes. It is a painful, disfiguring disease that may strike horses as early as 2 years of age, then over time cause formation of large nodules that interfere with normal pastern movement, permanent skin ulceration and lameness, eventually and sadly leading to the horses’ early death.

horse affliction chronic progressive lymphedema

horse affliction chronic progressive lymphedema These are pictures of a Shire with CPL who belongs to a friend of mine. You can see the nodules that form. Because of the dense feathering, this wasn’t noticed until it got advanced. The Shire was treated and the feathers have grown back he looks great and is doing well now!  (Photos Courtesy Barbara Willard.)

Treatment and Management of CPL
The most effective way to keep lymphedema under control is through the use of combined treatment approaches such as those listed below. It cannot be over emphasized that the sooner treatment starts, the better the results.

Clipping of the feathers-- 
Long and dense feathering makes management of lymphedema more difficult. It’s recommended to clip the feathers and keep them short. As the skin condition improves and the edema is reducing - you may have a better chance to keep the horse's legs in better condition by careful repetitive treatment, while the feathering is growing back. The feathers are usually back to their original length in about 10-12 months.
Treatment of skin infections
--  Progression of lymphedema is also associated with formation of fibrotic nodules. As a result, these horses have a poor blood circulation and immune response in the skin of their legs. The long feathering further blocks the skin surface, which then remains humid. These factors provide the perfect culture environment for infectious pathogens. This explains why horses with CPL constantly battle recurrent infections with mites Horses with CPL should consistently be treated against re-infestation of mites and bacteria.

Topical treatments--  Careful washing, cleaning and drying of the legs on a routine basis is essential. There are special skin treatment shampoos that you can purchase. Horses with long feathering may require blow-drying of their legs.

Frontline spray-- to treat chorioptic mange (a group of the mange mites family). Note: Do not use
Frontline on pregnant and nursing mares)

Sulfur powder--  The best and most economical topical treatment is to find a source of wettable sulfur powder (“flowers of sulfur”). This can usually be found through a vineyard supply or at your local nursery (certain “rose dust” preparations).

--  Regular exercise is crucial. It will increase the circulation and the lymph drainage.

Manual Lymph-drainage--
  MLD has been successfully used in horses with more acute lymphedema, but has not been established yet in horses with progressed CPL. A massaging cold water stream may assist a massage.

Bandaging --
There has been limited experience with using special bandages developed for humans with lymphedema. For horses, which always move around, “short-stretch” bandages should be used. Short stretch bandages have been successfully used in horses with clipped feathering; but bandaging was not as successful on horses with long feathers. Of course it is crucial to have very good padding and keeping the bandages fairly tight.

It should be noted that horses suffering from CPL often are susceptible to repeated bouts of thrush. Consequently, thorough and routine foot trimming care is an essential part of the health care management for these horses.