What is rain rot?
Rain rot is one of the most common skin infections seen in horses. It is also referred to as "rain scald" or "streptothricosis". The organism that causes rain rot appears and multiplies in warm, damp conditions where high temperature and high humidity are present. This condition is not life-threatening, so don't worry. However, while the horse has rain rot, any equipment that may rub and irritate the infected skin (such as saddles and leg wraps) should be eliminated.


What causes rain rot?
The organism dermatophilus congolensis causes rain rot. dermatophilus congolensis is not a fungus. It is an actinomycetes, which behaves like both bacteria and fungi. Most people believe that the organism is present in soil, however, this has not been proven. The organism is carried on the horse, who has it in his skin. A horse who has this organism in his skin may or may not be affected.


What does rain rot look like?
Rain rot can appear as large crust-like scabs, or small 1/4 inch matted tufts of hair. There is usually dozens of tiny scabs that have embedded hair and can be easily scraped off. Underneath the scabs, the skin is usually (but not always) pink with puss when the scabs are first removed, then it becomes gray and dry as it heals. It is usually hard to differentiate rain rot from other similar skin conditions, so if you are unsure, call your veterinarian.

In the early stages, you will be able to feel small lumps on the horses' skin or hair by running your hand over your horse's coat.
Click here for pictures of rain rot


In what region is rain rot most common?
Rain rot can be present in any horse around the world, but is most common in South Florida. In South Florida, the increased humidity and high temperatures combine with the prolonged rainfall to create the perfect environment for the organism to live.


What conditions are usually present?
1. The animal has to be infected with the organism. A horse can become infected by shared saddle blankets, leg wraps and brushes with other infected horses.

2. There has to be extreme moisture present. Horses with thick coats are more likely to keep the moisture close to their skin.

3. The skin has to be damaged (by a cut, scrape or insect bite), for the organism to be able to enter the epidermis.   Insect bites from gnats, no-see-ums, culicoides, mites, ticks, deer flies, horse flies, black flies, mosquitoes hornets, wasps, bees and chiggers are typically the culprits.

4. Also, poor stable management, damp stalls, poor ventilation and infected barns.


Will rain rot go away on its own?
It sometimes does. What I mean is that some horses will naturally get rid of the organism as they shed out their winter hair coat. However, it is not advisable to let the condition persist, you should not wait to see if it will go away...start treating it now, before it gets any worse!


Does rain rot lead to any other conditions?
Since the organism needs a warm, moist environment, it is likely that a secondary bacterial infection may become present. The most common secondary bacterial infections known are staphylococcus (staph), and streptococcus (strep). This is why it is very important to treat rain rot immediately, since any secondary bacterial infection may be even more resistant and difficult to treat.


How does rain rot spread?
The organism, dermatophilus congolensis, can be spread through sharing of equipment between horses. This includes saddle pads, blankets, leg wraps, brushes, halters, etc. It is extremely difficult to prevent the spread of rain rot, since a horse can pass it to another horse by simply rubbing it's skin on any object that the other horse may touch. The best prevention for rain rot is to use a disinfectant on any equipment shared between horses after each use.

When treating this condition, you must keep all equipment used on the horse disinfected, to be able to keep the organism from coming back. A good solution is 2 tablespoons to 1 gallon of water of Chlorox. Do not use this solution on your horse, only on the equipment!


Where does rain rot appear?
Usually on the horse's back and rump, along with the back of the fetlock and front of the cannon bone. It may also appear on the tips of the horse's ears and around the eyes and muzzle. When rain rot appears on the lower limbs (behind the fetlock), it is most commonly referred to as "dew poisoning".

How do we treat or control this condition ?
Calm Coat has been proven to be an excellent remedy for fast and immediate relief of Rain Rot (Fungus) and Sweet Itch... Recommended 7 times by horse journal!
click here for horse journal article...