Equine Pastern Dermatitis (EPD), aka “scratches,” “greasy heel,” or “mud fever” is a skin disease of the lower limbs. Most commonly seen on the hind limbs, the dermatitis affects the backs of the pasterns and occasionally moves to the front of the limb. Draft breeds and draft crosses with feathers on their distal limbs and horses with white socks (ie: unpigmented skin) are predisposed to this condition. It is often seen in horses in muddy paddocks, rough prickly pastures and unsanitary condition, due to the high Generally the overall health of the horse is unaffected but severe cases can cause distal limb edema (swelling) and significant lameness.
The causative agents are usually bacteria including, Staph. aureus or Dermatophilus congolensis. There can occasionally be a fungal component and horses infected with mites or lice are at risk for developing infection where the parasites break the skin. While the diagnosis is often made just based on clinical signs, the only way to truly know what’s causing the infection is to have your veterinarian perform a culture and in some chronic cases a biopsy is required.
Once the scabs are removed and the area is all suds up with an anti-septic solution such as 2% chlorhexidine, povidone iodine or benzoyl peroxide, I like to let the area sit for 5-10 minutes. This give the anti-septic plenty of “contact time” to kill the bacteria. After you rinse the cleanser off completely (dried soap can be irritating and itchy) the leg must be dried. And I mean really dried, not just wipe the excess water off with my hand like a human sweat scraper, or giving it one swipe with an already damp towl. The leg needs to be REALLY dry. For those of you with feathered horses who can’t bear the thought of clipping their lovely locks (or can’t for the summer show season) I recommend a hair dryer on a low setting to help really dry off the leg.