SKIN DISCHARGE (SEBORRHEA)
Horses with sensitive skin, such as Thoroughbreds and Arabians, are more prone to this complaint than other breeds; however, seborrhea (skin discharge) can develop in any horse as a secondary condition to skin infection or allergy, or it could be a signal of poor overall health. Seborrhea takes two forms, either dry or oily. Dry seborrhea exhibits dry, flaky scales that look similar to dandruff, and is found in the mane or tail. Thick, viscous crusts usually affecting the elbows or hocks are signs of oily seborrhea.
To treat, wash the area with a sulfur-based shampoo once or twice a week to manage dry seborrhea, although recurrences are common. For oily seborrhea, depending on the severity of the case, wash the area at least twice a week using a drying shampoo (that contains tar or benzoyl peroxide, for instance), followed by a protective ointment to soften the crusts.
DRY/ITCHY SKIN AND TAILS
If a horse’s skin becomes excessively dry and scaly, it can be pruritic, i.e., itchy. I recommend thoroughly washing the horse using appropriate shampoos, and apply sprays or lotions, such as Dr. Rose’s Treatment Spray (http://www.horsetackco.com/dr-roses-healing-spray-4-oz.html#.VKsrKye2jO0). After shampooing your horse with a soapy lather, make sure you rinse well. Shampoo or soap residues that remain on skin or tail can also cause itching.
Horses respond to physical or mental irritation with obvious behavioral quirks, sometimes inflicting harmful trauma on their own bodies. While a variety of problems can cause itching, a horse might concentrate his itch behavior on tail rubbing. There might be a couple of health issues going on simultaneously, so your veterinarian should rule out all possibilities of tail rubbing behavior with a diligent exam.
Once he or she addresses the primary problem along with appropriate behavior modification, the horse’s rubbing should rapidly resolve and his tail will return to its fullness and sheen.