CPL - Chronic Progressive Lymphedema

It's very common for people on the chat groups to post about scratches, greasy heel, dermatitis on the fetlocks and pasterns. Most of the time it can be treated with the appropriate antidote. Scrapings can help you determine if it's being caused by mites, fungus, bacteria. You can also evaluate your horses immune system to see if they are not defending themselves. This will not be a post on the million ways to treat scratches/greasy heel because if the test shows X then you treat with Y... so talk with your vet.....

But what about the times when NOTHING works. you treat all the fungus, bacteria and have your diet in check, feathers cleaned and dried, footing/bedding dry, moved locations, but the horse is still chronic. They even seem a little swollen in the lower legs. ......

They might have CPL. Many draft and feathered breeds suffer from CPL. Fenway Foundation and a few other research parties are trying to figure out why it happens a lot in Friesians LINK. There is no solid research results to support the claims that it's genetic or that it's environmental or that it's a collagen disorder. But  there are some blood lines that are believed to be more susceptible to chronic dermatitis on the lower legs. They have not actually compared affected horses in a lineage and documented the environment that the horses are in to determine if it's environmental. They are working on documenting affected bloodlines. UC Davis has some information online about it LINK

There is also no easy way to document the severity or to know if it's truly CPL or just scratches. For example we had a mare that we bought that was very scaled in her feathers, had giant lumps that were hard on her fetlocks. She came from a humid climate and was moved to a dry climate. We shaved the feathers, treated with bleach for 1 week and let the hair grow back. She never had scales again even when we moved to the beach in Australia. The lumps took a very very long time to go down and never went away completely. But exercise seemed to soften them and reduce them. So was that scratches or had she stayed in her original environment would she have been classified as having CPL. The lumps that would normally be classified as CPL, were they from chronic scratches in the form of scar tissue, or was it truly CPL that sent her in that direction in the first place. There is no real way to analyze this situation with so many horses in so many different locations.

With the very narrow breeding pool for the Friesians, it could also be a type of allergy that has not been figured out yet. Many inbreeding programs (human or animal) result in decreased immunity and an increase in allergies and insect hypersensitivity.

It's likely that a horse that has CPL tendencies will develop varying levels of CPL. Can be from periodic scratches (1) to inflamed legs that need pressure wraps with chronic dermatitis (10). Environment could take a horse that is a 2 and make it a 7, or vise versa. Or it could be that they are destined to be a certain severity. It's also likely that as the horse gets older they will be more affected. The lymph system is not as strong as they age. Their environment will continue to enable their secondary infections. Scar tissue will form and not heal.

There have been correlations with feathering density and tendency towards CPL, you also may notice that the KFPS stallion selection program is getting less and less feathering....

I would love to say that there is a cure or an answer but as of yet there is not. All you can do is treat the secondary infections and symptoms and hope that you can keep the horse comfortable. Some people have moved their horses to drier environments and some have had to stay on top of treatments regularly.