10/27/2025
IS RAIN ROT A FUNGAL OR A BACTERIAL DISEASE?
Rain rot (or rain scald) is the common name for a contagious BACTERIAL skin disease called dermatophilosis. It's caused by the bacterium "Dermatophilus congolensis," which thrives during wet seasons and in geographical locations with high precipitation and humidity. It can also develop after horses have sweat under blankets or tack, and equines with compromised immune systems are more susceptible.
Why should you not mistake rain rot for a fungal disease?
Antifungal medications and topicals have no effect on the bacteria responsible for rain rot, therefore diagnosing the condition correctly is very important!
How does rain rot happen?
The bacteria infects the hair follicles and damages the hair follicle and shaft; the hair will then pull out in small clumps leaving pink skin or purulent scabs behind (pro tip: your horse will NOT thank you for picking at them!) If you do not address the factors that promote the right bacterial environment (for example, you always leave your horse to stand outside in the rain without shelter or the protection of a waterproof rug), rain rot can keep recurring. If left untreated, the condition can even progress to a point where it opens the door for more serious, secondary skin infections.
If you suspect your horse has rain rot, be sure to consult your veterinarian on the best treatment plan based on the severity of your horse's case. While there are a million products that can be found in your local tack store, your horse doctor may have cause to prescribe a specific course of action.
