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Rain Rot in Horses

Rain Rot in Horses
By Brittani Kirkland and Ann M. Swinker
 
In periods of constant, frequent rain, it is important for horse owners to consider how rain may impact their horses, farms, and riding experiences. Rain rot is a common condition during rainy seasons and can be of concern for many horse owners. While typically easily treated, rain rot can be a serious issue and should be addressed immediately by the horse owner to prevent spread or worsening.
 
What is rain rot?
 
Rain rot, also called rain scald or dermatophilosis, is a skin infection caused by a bacterium known as Dermatophilus congolensis. Living on the horse’s skin, D. congolensis is mostly dormant, but under wet conditions, this bacterium can cause an inflammatory infection resulting in lesions along your horse’s skin. These lesions cause small patches of raised bumps which are scabs containing clusters of your horse’s hair. Removal of these scabs results in bald patches along the affected area. In severe cases, lesions and scabs may become large and affect multiple layers of skin. When this occurs, the horse’s use may be impacted until the infection clears.
 
While most often found on the horse’s topline, rain rot can be found on numerous areas of the horse’s body, including their rump, face, and legs. Therefore, it is important that regular, thorough full-body examinations occur. Hands-on palpation may be needed when examining your horse for rain rot, particularly during winter months, as increased coat length makes visual assessment difficult. Unlike many other skin conditions, areas with rain rot do not typically itch but can be painful and cause your horse to become sensitive to touch.
 
All horses can be affected by this condition; however, there have been identified links with horse’s coat colors and immune status leading to a higher incidence of rain rot. Particularly, horses with lighter coat colors as well as horses with compromised or poorly developed immune systems (such as young or older horses) have been found to be at higher risk. Specific environmental factors have been also been identified. Rain rot most often occurs when the skin has been compromised in some way. Compromise occurs during times of high humidity, prolonged rainfall, or increased exposure to biting insects. Horse owners should take steps to limit impact when these environmental conditions are present.
 
Prevention and Treatment of Rain Rot
 
Prevention
 
Practicing good hygiene habits with your horse such as regular bathing and grooming is one of the best ways to prevent rain rot from occurring. Likewise, reducing exposure to environmental factors known to increase incidence may help prevent this condition. If you know there will be heavy rainfall in your area, keeping your horse in a barn or under shelter can help reduce risk. Also, limiting access to muddy areas or trying to reduce the overall presence of mud may be helpful, as caked mud on your horse could compromise the skin. If you are seeing high biting insect populations, implement best management practices based on fly species. Some of these practices include setting up traps, increasing farm sanitation, introducing parasitoid wasps, and spraying your horse with a pyrethroid-based insecticide.
 
Treatment
 
If your horse has a minor case of rain rot, it can typically heal with a little bit of extra attention and care. Giving your horse a bath with an anti-microbial soap can help remove the scabs and disrupt the bacteria in the affected area. Additionally, currying and brushing your horse can help by promoting healing and preventing the spread or worsening of the area. As you work to remove scabs, the affected area may become tender to the touch so be cautious with removal. Softening the scabs first makes removal easier and more comfortable for your horse. There are also topical antimicrobial products you may want to include in your treatment routine if you find it necessary.
 
Keep your horse dry and reduce exposure to known environmental factors during treatment. You may also want to keep horses with rain rot separated from others while treatment is occurring to prevent spread amongst horses. Similarly, be sure to disinfect and replace contaminated grooming tools and other equipment as needed to prevent spread.
 
In severe cases, your horse may need antibiotic injections given by a veterinarian. Skin biopsies may need to be conducted to identify if the cause of the infection and ensure it is rain rot. It is always recommended that you consult a veterinarian in any case when determining cause and making treatment plans.
Source : psu.edu