Beneath The Surface of Rain Rot

Last Updated on February 19, 2022 by Allison Price

Learn more about the contagious bacterial skin condition dermatophilosis. Prevention is important and treatment is crucial.

A skin condition known as dermatophilosis (or rain rot) could cause matted tufts or crusty scabs to appear on the horse’s hair.

Courtesy of Cornell University College of Veterinary Medicine, Dermatology

You may notice that your horse’s coat has not been blooming as well after a wet spring, with heavy rains and the appearance fiercely biting insects. You may notice that your horse’s skin is dry and flaky. These signs are often due to a skin condition called dermatophilosis. It is also known as rain rot, rain scald or rain scald.

According to William Miller, VMD. DACVD, a Cornell University College of Veterinary Medicine veterinary dermatologist, Dermatophilosis can be caused by the bacterium . This disease is highly contagious and can be very painful in severe cases. However, it can be prevented by good grooming and careful horse care.

Dermatophilosis can be caused by the bacterium Dermatophilus consgolensis. It is usually found on the skins of many mammals.

Courtesy of Cornell University College of Veterinary Medicine, Dermatology

Rain Rot on Horses

What is Rain Rot?

Horses that have been exposed to rain or allowed to dry after taking a bath are not at risk of rain rot. Infection can occur if the horse’s skin is still damp or bacteria finds its way into his body through an insect bite or open wound.

Infection means that the normal skin barriers must be breached. Dr. Miller states that prolonged skin saturation in horses without drying can weaken the outermost layer of skin and allow for easy infection. “When the organism is moistened, it becomes flagellated (capable of moving in the area infected) and can spread to other areas of the animal’s body. Flagellated bacteria can be transmitted to other animals by insects and grooming tools.

Rain rot is more prevalent in wet seasons, where there is high humidity and precipitation. This creates the ideal environment for bacteria growth. Dry skin and loose hair are the signs of minor cases. Acute cases can present with large, matted hair clumps and scabs that feel tender and are difficult to remove. The scabs may also have a yellowish to greenish pus.

Rain rot can be found on horses’ backs and flanks, and anywhere moisture runs down the barrel, shoulders, and even the tops of the heads.

Courtesy of Cornell University College of Veterinary Medicine, Dermatology

Rain rot can be found on horses’ backs, flanks, and areas where moisture runs down the barrels, shoulders, and faces. Max Corcoran, a barn manager and professional groomer, notes that horses can get dermatophilosis if they have been exposed to sweat or blankets. Retired horses and those who aren’t in full-time work are more likely to be affected because they don’t get groomed as often or have thick winter coats that trap moisture for long periods.

Horses with compromised immune systems may also be at higher risk. Dr. Miller states that infection can be easier if the horse has an underlying immune, metabolic, or skin disease. If the organism is present on the horse’s farm, any disease that weakens or impairs the skin or immune system could lead to dermatophilosis.

You can identify rain rot by inspecting the affected area. Dr. Miller explains that if the horse develops a crusty, tender dermatitis on its topline after heavy rain, and little sunlight, it is easy to diagnose and will be treated by most veterinarians.

Horses can suffer from a variety of fungal and bacterial skin conditions. A veterinarian can scientifically diagnose dermatophilosis in order to clear up any doubts about the best way to proceed with treatment. Dr. Miller states that it can be difficult or easy to diagnose dermatophilosis. To prove the diagnosis, the organism must be confirmed by cytology, a bacterial culture, or a skin biopsy.

Treatment Options

Call your veterinarian if you suspect that your horse may have rain rot. Together, they will determine the best treatment.

First, protect the area from moisture exposure and allow oxygen to reach the skin. Before you put on any new sheets or blankets, let the horse air dry.

Your veterinarian might recommend that you have your skin cleaned. This could be all that is needed.

If the scabs become large and hard to remove, you might need to use a comb or gloved hands to get rid of them. You may find sores or bleeding. The condition may cause tenderness and pain for your horse. Be prepared to respond when you remove the crusts from the skin. Dr. Miller warns that latex gloves are recommended as “the organism could infect humans through small cuts and other defects in their skin.”

topical treatment can be applied to the affected areas to kill the aggravated bacteria. Dr. Miller explained that many antibacterial products are effective, particularly those containing chlorhexidine or tamed Iodine. You can find some formulations at your local tack shop, but your veterinarian may prescribe a specific treatment.

You should clean the affected area of the coat and gently remove the crusts. They can still be infected if you throw them out.

(c) Dusty Perin

Sometimes, only topical treatments are not enough to cure the problem. Dr. Miller states that systemic antibiotics will likely be required to complement the topical treatments in cases of hair follicle infection or chronic, widespread disease in horses.

If the scabs have become large and hard to remove, it might take several days to groom, wash, and treat to make any progress.

The contagious bacteria can still be found in the crusts that have been removed. Burn the crusts or throw them in the trash. Dr. Miller explains that in acute dermatophilosis the organism is found on the skin’s surface, and trapped within the crusts. To prevent contamination of the farm, it is important to dispose of any crusts that have been removed.

Keep your horse’s affected areas clean while he heals from the rain rot. Avoid covering the lesions using boots, wraps or saddle pads. These items could cause a reopening of a wound, or expose it to dirt, grime, and dirt.

Rain rot can be contagious. Any grooming tools and tack that come into contact with infected horses should be cleaned thoroughly and not shared with others.

(c) Paula Da Silva/Arnd.nL

Rain rot can be contagious to humans, animals and horses. After contact, all brushes, buckets, and blankets should be cleaned thoroughly and not shared with any other horses. A good rule of thumb is to keep infected horses separate from other farm animals.

Rain rot can be mild and will resolve with good nutrition and improved weather. It is important to act quickly and effectively to stop the disease spreading and prevent any discomfort. Secondary infections can occur if the disease is not treated promptly. Dr. Miller explains that wild animals, including wild horses can contract clinical diseases. Most will self-cure it when the rain stops and the sun shines and the quality and quantity of their forage increase. This will also happen with a healthy horse but the horse will feel uncomfortable while it waits for self-cure. It will also be a source of infection for other farm animals.

Prevention Is Better Than Cure

Max believes prevention is the best treatment for rain rot. She is responsible for caring for both retired and active competition horses. It all comes back to basic horsemanship. Every day, every horse should be given a thorough check to ensure there aren’t any cuts, swelling, or injuries. It is vital for their health. After your horse has been in the rain for more than two days, you should check for rain rot.

(c) Frank Sorge/Arnd.NL

Max suggests that blankets be removed every other day during the cold season to inspect the horse’s skin and body. Allow blankets to remain on the horse’s skin for as long as possible. Make sure to check your horse’s blanket regularly and take it off if necessary.

She continues, “The horses should be given a minimum of a curry brush and a brush every few days, even retired horses or horses that are pasture-boarded.” You don’t need to bring them in to make them look pretty. Just get rid of the dirt. This is a great time to check for any hair growth and remove it.

Don’t blanket horses who are still wet after a bath, or have damp, sweaty hair from a workout. She says that some people leave saddle-pad spots after they body clip. However, I have seen horses sweat beneath it and just brush it quickly. Before you put on a blanket or sheet, let even a small amount of hair dry completely.

Rain rot can be prevented by regular grooming and paying attention to blanketing. Horses who live outdoors 24/7 or don’t get groomed often will benefit from a sturdy roofed or run-in shed. The best way to dry your horses’ coats faster is to drain excess water from their baths. Insect repellant will lessen the urge to scratch and reduce the likelihood of skin imperfections and bites from bacteria.

Rain rot is a serious condition that can cause discomfort, pain, hair loss, or even death in horses. Early treatment will help to prevent any further problems. You can prevent future problems by giving your horse good care and regular grooming.

Bacterial Vs. Fungal

Dermatophilosis can be confused with other skin conditions and fungal diseases. Fungi can be found in a wide range of environments, but they can also cause illness when inhaled or swallowed.

Ringworm is a fungal disease that thrives on Keratin, a protein found in hair and skin cells. Ringworm is characterized by dry, crusty skin and hair loss. Although itchy lesions may appear red or tender, they can also be itchy. Ringworm can be serious and you should contact your veterinarian immediately. Ringworm is very contagious and can live for long periods of time on many surfaces around the farm.

Use latex gloves to handle ringworm-infected horses. Disinfect all equipment used for grooming, riding, and feeding. To prevent the disease spreading, keep him away from other horses.

Pastern dermatitis (also known as dew poisoning or scratches) can also cause rain rot. It is possible to confuse the two. Horses that live in wet or muddy environments are more likely to get it. White socks and horses with a lot of white hair may also be more vulnerable. Scratches are most common on the lower limbs, particularly the back of the pastern and fetlocks.

Pastern dermatitis (also known as dew poisoning or scratches) can be difficult to distinguish from rain rot. However, a vet exam can help ensure that a diagnosis is made and the right treatment is given.

(c) Arnd Bronkhorst

Horses can feel very pain after a scratch. The area may become inflamed or scabby. It is possible for the skin to appear cracked and even to bleed. The leg can become hot and swollen, which may cause discomfort and possibly lameness.

Open sores and scabbing caused by scratches can open the door to other bacteria. This is especially true if the injury occurs on the lower leg. A horse with scratches should be kept dry and clean in a stall or paddock for as long as it takes to heal.

Max Corcoran says that she is very aggressive in treating horses with scratches, particularly horses in full work or actively competing. Horses may not be able wear boots or exercise because of inflammation in their legs and painful sores.

The treatment for scratches will vary from one horse to another because it is multifactorial. For the best possible treatment for your horse, consult your veterinarian.

Antibacterial medication and soaps should be used to treat bacterial infections. However, it is important that fungal infections are treated with antifungal creams. The area should always be kept dry, clean, and open to the air.

Allison Price
Allison Price

I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!