How to Treat Rain Rot in Horses
Rain rot, or rain scald, is a bacterial skin infection that is common in horses, particularly in humid, wet weather. The correct veterinary term is "dermatophilosis." Rain rot thrives in a moist, warm atmosphere and is more common in the spring and summer when the rains and higher temperatures provide a breeding ground for this nasty bacteria. It also crops up in winter, especially if temperatures rise and fall and horses are sweating under their blankets as the temperatures get warmer throughout the day.
The most common symptom of rain rot is hair loss. If your horse has rain rot, you will notice the hair rise up in tufts and it will fall out if rubbed or brushed. A mild case will leave smooth skin underneath; a severe case will leave small scabs or sores. Rain rot in horses looks similar to mange in dogs, but is not the same thing and cannot be treated the same way.
Rain rot can be a sign that a horse is not being cared for properly, but this is not always the case. Some horses have sensitive skin and are more susceptible to rain rot. Horses in the American South are also more susceptible simply because the weather is hotter. Rain rot is awfully hard to get rid of once a horse has contracted it, so we will look at how to prevent as well as how to treat it.
First, prevention! If your horse is living in a pasture setting and has a run-in shed but no enclosed stall, he will get wet. Horses don't seem to mind the rain like people do, so your horse is likely to stay out in the open under light rain. This is okay. Many horses seem to be happiest living outside 24/7, so don't feel like you need to run out and put your horse in the barn every time it sprinkles. If he rolls in the mud however, try to get him cleaned up pretty quickly. Rain rot is believed to be found in dirt, so keeping his coat clean could lessen his chances of contracting it. If your horse has had rain rot in the past and seems particularly susceptible to it, you may have to resort to keeping him stalled and dry in wet weather. Essentially, keeping your horse as clean as possible is your best defense against rain rot.
Now, if your horse already has a case of this nasty stuff, you have to determine how bad it is. Does your horse have raw looking skin or sores where the hair has fallen out? If he does, you need to call your vet. Putting medicine on raw skin can be terribly painful, so you want to get your vet out before you put anything on your horse that could make the problem worse. Antibiotics are usually prescribed in severe cases to help a horse fight off the bacteria.
If your horse's hair tufts up and falls out when you scratch it, but the skin underneath is smooth and not irritated, he has a mild case. You have several options. The first, my favorite and the cheapest, is Listerine. The original golden colored Listerine is what I use on my horse and it works quickly. Get a spray bottle, fill it with Listerine and spray the affected areas. You should take your fingers and brush the affected hair. A curry comb will work as well. The sooner the hair falls out, the sooner your horse can start new hair growth. Brush and spray, brush and spray. Do it every day! If the hair doesn't come out easily, don't force it. Just spray the area. When it's ready to come out, it will, with very little effort.
You can also use M-T-G spray. It's about $16 for a spray bottle. It is sulphur based and smells awful, but will work to kill the bacteria. Do the same thing as with the Listerine. Remove the affected hair and spray the area. I have heard some people say that a bleach/water mixture will work (1 part bleach to 10 parts water), but I would be careful with this. If your horse does have scabs or sores, this will burn him.
Next, you have to clean everything that comes in contact with your horse or you will end up spreading the bacteria. Brushes, combs, saddle pads, blankets, and the like should all be washed immediately to avoid further spreading rain rot. I do soak my brushes in bleach water. It doesn't hurt the brushes, but it will kill rain rot for sure.
Rain rot looks nasty and is a pain to get rid of because it tends to spread quickly. In the grand scheme of horse illnesses and injuries however, it's pretty mild. Yes, your horse will have some bald patches, but he will recover good as new within a couple months as long as you're vigilant about treating him. Take heart, it could be much worse!