“THOSE DREADED CRUSTY AND ITCHY SCABS ARE BACK.”

From: Erica Larson, News Editor | The Horse

Those dreaded crusty and itchy scabs are back. You know the ones. They cover the back of your horse’s pasterns, sometimes spreading to his fetlocks and further. And the worst part of this so-called equine pastern dermatitis (or EPD, often referred to as scratches) is that you know you have an uphill battle in front of you—successfully returning your horse’s affected skin to health is a notoriously difficult task.

So what’s new in diagnosing and treating EPD? Anthony Yu, DVM, MS, Dipl. ACVD, reviewed how to diagnose and treat this frustrating problem at the 2016 Western Veterinary Conference, held in March in Las Vegas. Yu is a board-certified veterinary allergist and dermatologist and owns Yu of Guelph Veterinary Dermatology, in Guelph, Ontario, Canada.

One key thing to remember about EPD, Yu said, is that it is not, in itself, a single disease. Rather, it’s a symptom of a variety of underlying conditions. As such, accurately diagnosing which condition your horse is afflicted with is essential to prescribing the proper treatment.

And, he added, “to achieve a positive therapeutic outcome, treating the predisposing and perpetuating factors is just as important as addressing the primary cause of EPD.” In short, it’s a complex process.

WHAT DOES IT LOOK LIKE?

Pastern dermatitis isn’t fussy about what kind of horse or pony it affects—equids of all breeds, sexes, and sizes can develop the condition. However, Yu said, horses with feathers are more commonly affected, as are adult horses compared to foals, and hind limbs are more likely to be affected than forelimbs. Lesions develop more frequently on white areas of the lower limbs, but develop on pigmented skin, as well. Left untreated, said Yu, lesions could spread from the back of the pastern (the most commonly affected area) to the front of the pastern and fetlock.

Clinical signs vary depending on the cause of EPD, but often include edema (lower limb fluid swelling), erythema (reddening of the skin), and scaling, which can progress to exudation (oozing scabs), hair-matting, crusting, fissures, and thickened skin. Ulcers and secondary bacterial infection can also develop in some cases.