Chronic Progressive Lymphoedema

Welcome to the world’s first comprehensive guide to CPL for owners, veterinary professionals and complimentary therapists in the equine industry.

What is CPL?

Chronic Progressive Lymphoedema is a disease affecting draft horses and cobs with feather.

The lymphatic drainage in the legs fails, causing inflammation and fibrosis. The horse will have hyperkeratosis, unrestricted to the typical areas (“mallenders and sallenders”). CPL is unique in it’s physical presentation and can be diagnosed on that alone. Invasive procedures to diagnose are unhelpful, unnecessary and can be harmful.

For a detailed explanation of CPL, click here.

CPL is frequently misdiagnosed as feather mites, “cob legs”, scarring and mud fever/greasy heel. These horses are also prone to chronic thrush which can be treatment-resistant and can develop laminitis.

CPL causes the legs to be immuno-compromised so the risk of secondary infection is higher than in non-CPL horses.

It is important to note that feathered horses, especially with CPL, are prone to hyperkeratosis (an over-production of keratin) which causes skin crusts on which feather mites feed. Left untreated these mites can cause scarring and damage to the delicate tissue and superficial lymph vessels and as such must be recognised as one of the major triggers of CPL.

The major factors affecting CPL are as follows: –

Feather mites
Poor husbandry/hygiene
Inappropriate diet
Restriction of movement
Hyperkeratosis
Obesity

CPL can be effectively managed and even reduced by addressing the disease holistically and following the CPL Management Protocol:-

Clipping
Species appropriate diet
Hoofcare
Exercise
Turnout/track systems
Eradicate feather mites
Hygiene/leg washing
Topicals and emollients
Combined Decongestive Therapy
Medically Correct Compression/Multi-level lymphoedema bandaging

CPL can occur on it’s own or alongside another disease called Chronic Proliferative Pastern Dermatitis (CPPD), also known as “verrucous pastern dermatitis”. In the past the two have been confused in descriptions, but they are separate diseases. You will not see a horse with CPPD that doesnt also have CPL. CPPD has also been linked to feather mites.

“C.bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruciform lesions.”


Silvia RüfenachtPetra J. RoosjeHeinz SagerMarcus G. DoherrReto StraubPamela Goldinger‐MüllerVincent Gerber
Early (score AA) CPL.
Severe (score C) CPL
Vitus the Brabant
CPL Nodules – round, flat and clearly demarcated.
Not to be confused with Chronic Proliferative/verrucous Pastern Dermatitis.
Often this fold is the first indication of CPL.

Is this CPL?

In yellow is a crease caused by hyperkeratosis. It is essentially “mallenders“, just further down the leg. Once the area has been allowed to scar like that it can create problems for the superficial drainage as the lymph can not pass through scar tissue thicker than 4mm.

Creasing like this can be prevented to some degree by applying an emollient regularly and using something like Sebolytic® shampoo to remove the keratin build up and restore the natural balance of the skin.

Photo credit Ebony Webster

We will see oedema start to develop around crease and gravity will bring that further down around the joint – see the minor folds developing, highlighted in red. Regardless of whether we think the horse will develop actual CPL, the best course of action is to treat as though it is, while also remembering to apply emollient to the area to prevent any further keratin build up and scarring. The area directly around the ergot may become puffy.

Below we can see two more unfortunate examples of this hyperkeratosis creasing and the subsequent oedema and loss of definition, as the leg starts to develop the familiar “traffic cone” shape and folds.

This example has also been affected by MASD (moisture associated skin damage) prior to clipping.
An example of the same scenario but further advanced in this case, note the puffiness to the area around the ergot and directly above and below the deep crease. These horses will likely benefit from CPL management protocol because they now have insufficiency in the superficial lymphatic drainage.
“Mallenders” – hyperkeratosis behind the knees.
Hyperkeratosis is simply an excess production of keratin which presents as crusty build up and flaky skin but can cause scarring and become infected.

Thanks to the members of the CPL Facebook Group for submitting the above images.