How to Prevent and Treat Rain Rot on Horses

Posted by Kat Tretina

Rain rot, known by veterinarians as streptothricosis, is a common skin infection in horses.

Rain rot is a fungal condition that can be contagious and spread throughout a herd. For years, rain rot was thought to be caused by organisms in dirt or soil, but recent research shows that it is dependent on a carrier animal who has the organism on its skin.

What is rain rot?

horse with rain rot

Rain rot is not life-threatening, but a horse with the infection will be itchy and uncomfortable. When the organisms develop, the coat will develop crusty scabs or small matted bunches of hair. There can be dozens or even hundreds of scabs or tufts that can be easily scraped off.

Underneath the crust, rain rot makes the skin pink, tender and sometimes it causes pus to develop. As it heals, the affected area will turn very dry and gray until it heals completely.

How do horses get rain rot?


Some horses are more susceptible to rain rot than others; some equines can be carriers, without showing any symptoms themselves.

In order for a horse to develop the infection, several variables must exist. They need to come into contact with an animal who is carrying the infection; this can be from sharing a pasture but also if you use the same brushes or saddle pads on different horses.

The environment needs to be very moist for the organisms to develop, so periods of heavy rainfall, humid climates, and foggy conditions can encourage rain rot to develop. Hot and humid areas like Florida are prime breeding grounds for the fungal condition to develop. Horses with thicker and longer coats also hold moisture against the skin longer, allowing the infection to take hold.

How is rain rot treated?


To eliminate the fungus in the coat, there are several steps:

  • Quarantine: Once you have found a horse that has developed rain rot, separate that horse from the rest of the herd and make sure any brushes or blankets the horse has come into contact with are thoroughly washed and disinfected before using on another animal.
  • Clip: If your horse has a dense coat, it is a safe harbor for fungus. Clip the coat if possible to allow more oxygen to get down to the skin.
  • Bathe: Using an antibacterial and antimicrobial shampoo, thoroughly lather the horse and allow him to stand with the shampoo on for at least ten minutes. As long as the horse has rain rot, he should be bathed in this manner daily.
  • Remove Scabs: Remove the scabs from the skin. This process can be painful for the horse, so go slowly and be gentle. It is usually easier to remove them after the bath while the horse is still damp, as the scabs will be moistened and softer. Use a curry comb or scraper to get the scabs off.
  • Treat: In some cases, just bathing with shampoo and removing the scabs will be enough to cure rain rot. However, other horses will need more intensive treatment. If your horse has a severe case of rain rot, contact your veterinarian. She will prescribe a course of antibiotics and immune system-boosting supplements to help fight the infection.

Rain rot can seem like a scary ailment when it first appears, but know that it is treatable and preventable!

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How to Prevent and Treat Rain Rot on Horses