How to Identify Horse Skin Diseases and Conditions

Rain Scald or Rain Rot

Sometimes a run of damp, rainy weather is all it takes for a horse to develop rain rot or rain scald, also known as dermatophilosis. This is a minor bacterial infection of the skin that occurs frequently in wet, humid weather. This weather causes a specific species of bacterium to proliferate and colonize weak areas in your horse's skin. As a result, the hair on your horse's back and rump will look like paintbrushes -- clumps of elevated hair tufts that fall out when you pick them, leaving raw pink skin underneath.

Most cases of rain rot will heal on their own with good hygiene and adequate drying time. You may have to keep your horse indoors for a period of time to allow the skin to dry and heal. More severe cases may make your horse's skin tender and require an anti-bacterial, drying shampoo. Ask your veterinarian for advice if you think your horse's rain rot is chronic or causing him to be uncomfortable.

Ringworm

Ringworm isn't caused by a worm. Instead it's a fungal infection and is zoonotic, meaning you can catch it from your horse. This infection makes your horse's skin appear scaly and scabby. Although sometimes the lesions are in a ring, they are not always in this shape. This condition is highly contagious and the fungus can remain in the environment for a long time.

Although most cases of ringworm will heal on their own, this can take several weeks to months. This usually is too long a period to wait due to how contagious and zoonotic this infection is. Instead, many vets will advise special topical treatments to help speed up the healing process. Along with treating the horse, all tack, grooming equipment, halters, blankets, and other equipment will need to be carefully sanitized. Handle horses with ringworm with disposable latex gloves. Be sure to carefully wash your hands and clothes after contact.

Mange

Mange is a skin condition caused by microscopic mites. These mites burrow or bite into the horse's skin and cause intense itching. Very young horses, senior horses, and horses in poor condition are more likely to be affected by mange. There are a few different types of mange, and they show up on the horse's skin in slightly different ways.

Lice

A few specific species of lice live on horses. Lice are species-specific, meaning horse lice only infest horses, human lice only infest humans, etc. This means you will not get infested from lice from your horse. Most lice infestations in horses occur on animals that are thin, stressed, and in poor health. Lice make horses extremely itchy. Severe infestations can make a horse anemic and weak. If your veterinarian diagnoses a lice infestation, she will likely treat your horse with a dewormer that is also effective against ectoparasites.

Allergic Dermatitis

Some horses have sensitive skin and may break with hives or rashes after contact with various substances, including plant particles and other substances in the air, or with food. Allergic dermatitis can show up on any part of the horse's body. Your and your veterinarian may have to do some detective work to figure out what is causing your horse's skin reaction. The cure may be removal of the cause and perhaps some anti-histamines if the skin irritation is really uncomfortable.

Greasy Heel or Pastern Dermatitis

Greasy heel, also known as mud fever or pastern dermatitis, is a generalized dermatitis that causes the skin around a horse's ankle to appear greasy. As the condition progresses, the skin can become inflamed, swollen, and hot to touch with scabs. Some horses will be tender and some become lame. The most common treatment is to keep the horse's feet dry and clean and apply antiseptic washes and ointment to the affected areas.

Vitiligo

While a horse with flashy white markings is undeniably eye-catching, white markings that suddenly appear around eyes and other thin-skinned areas on the horse leave many horse owners worrying, but this mainly a cosmetic issue. Caused by an auto-immune response where the horse's own pigment-producing cells die, this condition is not painful for the horse and not contagious. There is no treatment.

Summer Itch or Sweet Itch in Horses

Sweet itch is the common term for a skin allergy to biting midges, sometimes called no-see-ums. Some horses are allergic to the saliva of these tiny biting insects and their skin over-reacts, causes the horse to be extremely itchy and miserable. The best treatment for this condition is to prevent midge bites by using insect repellents and fly sheets on your horse during seasons when these insects are out. Your veterinarian may also prescribe antihistamines, such as hydroxyzine and cetirizine.