A skin infection in horses commonly known as rain rot, rain scald, dew poisoning, scratches, mud fever, and grease heel (depending on which part of the body it appears on) can be a particular problem for your horse during the wet months. Rain rot, which causes scabbing and patchy hair loss on your horse, is caused by Dermatophilus congolensis, an organism that behaves like both a bacteria and fungi. It thrives in conditions of high humidity and warm temperatures.

Some horses seem more susceptible to rain rot than others, especially if their immune systems are compromised by factors such as age, stress or poor nutrition. The organism also tends to multiply under cover of long hair, so horses who have not yet lost their winter coats, or tend to have thick leg hair, may be particularly vulnerable as temperatures rise and the rainy season hits. The infection takes hold in skin that has been scratched, broken or irritated in some way, and may be seen on the back, neck, face, ears and legs.

Dermatophilus congolensis can spread from horse to horse through shared brushes, blankets, leg boots and other items. Avoid using tools communally until you’ve cleared up the problem, and be sure to thoroughly disinfect all your equipment.

To treat rain rot, take the following steps:

• Keep the horse out of the rain, mud or dew-laden pasture.

• Gently remove the scabs and expose the infected skin to the air.

• Trim long or thick hair to approximately 1/4-1/2 inch. Scissors are best.

• If you use clippers, avoid nicking the skin, which could cause the infection to worsen and spread.

• Clean clipper blades with 90% isopropyl alcohol.

• Bathe the infected skin and surrounding area using an antimicrobial shampoo or veterinarian-recommended surgical scrub daily for 3-5 days.

• Keep the affected area dry and clean.

• If you don’t see obvious signs of healing within the first week, have your vet examine your horse for secondary problems and infections.

• Consult with your veterinarian about ways to boost your horse’s immune system.