Rain Rot in Horses

Rain Rot in Horses and Treatment

With the ridiculous amount of rain that the area has been dealing with lately, there are many things to take into account when you have horses. One of those things is rain rot.  If you (or your horse) live in an area with wet or very humid conditions, your horse might be at risk of contracting “rain rot”, which is a bacterial skin disease. Keep reading to learn what causes rain rot and how to successfully treat and prevent it.

Causes of Rain Rot

Rain rot (also known as dermatophilosis, rain scald) is caused by a bacterial infection, and it often is mistaken for a fungal disease. The bacteria live in the outer layer of the horses skin and cause crusty scabs that can range in size from very small to large.

Dermatophilus congolensis, the bacteria that causes this infection, lives in dormant within the skin until the skin is compromised which can happen when the horse is in a very wet area for a period of time, high humidity, high temperature, or by biting insects. The warm temperature paired with high humidity can also cause an increase in the number of biting insects (particularly flies and ticks) present that can spread the infection from horse to horse.

Diagnosing Rain Rot

It is usually very easy to diagnose rain rot by seeing the scabs in the affected area, but a more definite diagnosis can be made by examining a skin scraping under a microscope or by culturing the bacteria. Horses that still have their long winter coats will develop what are called “paintbrush lesions” (raised, matted tufts of hair) along their dorsal surfaces, which include their neck, withers, back, and croup, as well as on their legs. As the lesions get larger and join together, they will form a large scab that when removed will expose yellow-green pus between the necrotic and living skin layers. If this area is rubbed, the “scabs” may come off, exposing a hairless portion of skin.

How to Treat Rain Rot

Most cases of rain rot can heal on their own but it is always a good idea to have your vet assess the area to be on the safe side. With very simple cases you can wash the area with antimicrobial shampoos and enlist the help of a curry comb to take care of the problem. Unlike most skin conditions, rain rot is not itchy, but it can be painful for the horse when touched. Be cautious when bathing or removing the scabs. The area can also be painful to riding horses if it is present in the saddle area.

Being Proactive at Preventing Rain Rot

Practicing good hygiene, such as daily grooming with clean brushes, along with reducing constant wet and/or humid environments and biting insects are the best ways to prevent your horse from getting rain rot. Since rain rot can spread to other horses, it is very important to isolate a horse that is dealing with rain rot so he can’t pass it on to his pasture-mates. Make sure to use clean brushes and grooming tools on each horse and disinfect these items between each use.