Everyone wants their horse to have a perfect coat and be free of skin problems. The reality of it is that a variety of skin issues are fairly common in horses and you need to be armed. Skin disease spreads quickly and can be a disaster if you don’t know what you’re dealing with.
Commonly known as ”rain rot” or ”rain scald,” this organism flourishes under dense winter coats. The first sign of a problem is usually small tufts of several hairs each that are standing on end. Under these tufts are scabs, which will take the hair with them when they come off, leaving a raw spot.
If untreated, these spots will spread and often coalesce. Any horse can develop this infection, but it is most likely to occur in horses with compromised immune systems from malnutrition, old age or diseases like Cushing’s.
Aka ”scratches,” this is a fungal, bacterial, Dermatophilus or mixed infection of the skin on the back of the pastern. It likely gets started when particles of dirt get trapped in the skin folds and are held there by sweat or moisture. The organisms that invade this irritated skin depend upon what’s in the environment and the individual horse’s usual skin organisms.
Horses with trace-mineral deficiencies compromising their immune systems may be more susceptible. Because there is so much movement of the skin in this area, early attempts at healing can be pulled apart and heavy scabbing is common.
A hypersensitivity/allergic reaction to the Culicoides midge (see May 2009), ”sweet itch” is definitely the most common problem in this category, but sensitivity to any biting insect may develop. Reactions range from mild skin scaling to itching so intense the horse will rub the area raw. Tick bites along the mane or tail can also trigger this reaction.
Mites and Lice.
Rare in horses, they are most likely to strike malnourished, older or immunocompromised horses. Hair loss, intense itching and heavy skin flaking, sometimes skin thickening, are the hallmarks.
Ringworm is the most serious of the skin infections, causing itchy circular patches of hair loss that spread outwards from the center, healing of the center often occurring as the lesion progresses. Lesions appear gray and flaky, with broken hairs.
The most severe form is caused by the fungus Trichophytum, which can spread to humans. Trichophytum infections usually cause itching, while milder infections with other fungal strains will not. If your horse has an infection that looks like ringworm and is also itchy, call your vet.
You want the heavy guns (prescription remedies) to deal with this. Very young, debilitated/malnourished and immunocompromised horses are at greatest risk. Bacteria as the primary cause of skin problems is rare, but secondary infection can occur in any area with broken skin.
The normal reaction of skin to any irritation is to step up its production of protection for the outer skin layers, which causes flaking. A low-grade infection may be the cause, but chemical irritants, allergy or simply insufficient grooming may also be involved. Horses with a chronic illness of any type may also develop skin issues, as vital nutrients are diverted to tissues that need them more.
Should You Self-Treat'
There’s never any substitute for having a firm diagnosis when your horse has a problem, however skin problems are not life-threatening and minor ones often do respond to medicated shampoos and other treatments between shampoos. Attempting to deal with the problem yourself first is reasonable, if you follow some common sense rules:
• Wear gloves when grooming a horse with a skin problem and handling medicated products.
• Do not share grooming equipment, sponges, bath buckets, tack or blankets used for skin problem horses with other horses.
• If the problem doesn’t improve within a week or worsens, call in your vet.
Medicated shampoos should only be used when the horse obviously has a skin problem that calls for antimicrobial effects. The shampoos we tried contained a variety of active ingredients. On the herbal end, tea-tree oil is a good choice for both antibacterial and antifungal effects. Aloe is a common inclusion and helps by soothing and encouraging healing rather than antimicrobial effects.
Some shampoos still include iodine but their concentrations are only half of what you find in iodine-based skin scrubs. Iodine’s drying and irritating effects can only be prevented by skin conditioners and aloe.
Phenol (carbolic acid) was the first disinfectant used for surgeries, back in the late 1800s. It’s also an effective local anesthetic in open wounds, but concern about potential for tissue damage has led to use of more modern disinfectants.
Benzalkonium chloride is the active ingredient in hand sanitizers, diaper wipes and some dandruff shampoos. Triclosan is a widely used antibacterial with antifungal activity as well. Another common ingredient is PCMX (chloroxylenol), which is a rapid acting antibacterial and antifungal with very low toxicity.
The best antimicrobial in the world won’t do any good if it can’t get at the organism. The ability to effectively soften and release dense buildups is therefore important.
The two stand-outs for softening scabs and removing heavy buildup were Premium Horse Shampoo from Miracle Coat and Espree Tea Tree Medicated Shampoo. We are hard-pressed to pick between them for effectiveness and, since they are similarly priced (undiluted), let sales be your guide.
For treatment of difficult problems like rain rot and heavily scabbed scratches, we got the best results combining a medicated shampoo with a medicated topical spray or cream to use between baths.
Our top choices are perennial favorite EQyss Micro-Tek and newcomer Absorbine Medicated Shampoo and Spray. Both are effective, gentle and pleasant to use.
To help prevent secondary infections in a horse with midline dermatitis or sweet itch, consider Su-Per Antifungal Shampoo from Gateway, our Best Buy.
Article by Veterinary Editor Eleanor Kellon, VMD.