Here’s how one veterinarian treated a particularly challenging case of this common skin condition

When Sarah Pell, DVM, of Genessee Valley Equine Clinic (GVEC), in Scottsville, New York, visited a regular patient in the height of mud season, she wasn’t surprised to find the 18-year-old Quarter Horse gelding had pastern dermatitis, also known as scratches, mud fever, dew poisoning, or greasy heel. The skin condition, which commonly appears on the heel bulb, pasterns, and around the fetlocks, is triggered by wet conditions, including mud, standing water, and damp bedding. Bacteria and fungi living in these conditions find their way into even the smallest cracks in the skin, creating an infection.

“Mud season,” which used to be confined to fall and spring in New York state, now often extends into January and February. Like most horses the practice sees, the gelding was on turnout during the day and brought into his regularly cleaned stall overnight for the winter months.

In consistently moist conditions and/or stalls that are not cleaned enough, it’s not uncommon to see horses with scratches, says Pell. There are many over-the-counter topical protocols that owners typically try prior to calling Pell and her colleagues at GVEC out for evaluation.

“We have conversations (with horse owners) about scratches mostly during annual wellness visits unless the scratches have become severe or cause secondary problems like infection, swelling, or lameness,” she says.

That was the case for this Quarter Horse. During his annual physical exam, his owner mentioned that the horse had developed scabby crusts on the pasterns of both hind legs.

“The crusts were moderate and did not appear to be super painful,” says Pell. “In severe cases, we have to sedate the horse to work on the lesions because the leg is so painful to the touch. When I see a case of scratches like this, one of the first steps is to clip away the hair surrounding the affected area.”

While scratches can appear in any horse, they are more common in breeds with heavy feathering. The excess hair traps moisture close to the skin, creating the prime conditions for pastern dermatitis to develop. Clipping the hair around the pastern and fetlock allows moisture to wick away from the skin and gives it a chance to dry out.

After clipping the hair, Pell instructed the owner to shampoo both hind legs daily for one week using Betadine scrub (dilute) or Selsun Blue medicated shampoo. For best results she advises letting the shampoo sit for 10 minutes on the affected area before rinsing. After seven days she told the client to continue the washing protocol two to three times a week for several weeks. She instructs owners to avoid picking at or pulling off the scabs despite how tempting it may be