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Treatment and Causes of Rain Rot in Horses, Dogs, and Cats

I have had to treat my own horses' skin infections, so I am sharing the methods that have worked for me.

Have you ever witnessed rain rot in dogs? What about horses or cats? It's not a pretty sight. In this article, you'll learn about rain rot and how to best prevent and treat it.

Have you ever witnessed rain rot in dogs? What about horses or cats? It's not a pretty sight. In this article, you'll learn about rain rot and how to best prevent and treat it.

What Is Rain Rot?

Rain rot (also known as rain scald, dew poisoning, dermatophilosis, or mud fever) is a common and highly contagious skin infection that occurs in dogs, cats, horses, cattle, sheep, and a wide variety of wild animals. It is caused by dermatophilus congolensis, a facultative anaerobic bacterium.

This type of bacterium can use oxygen when it is available or switch to anaerobic metabolism (fermentation) when it is not. D. Congolesis generally affects the epidermis. The bacterium causes the skin to scab, resulting in hair loss.

Example of a moderate case of rain rot in a horse.

Example of a moderate case of rain rot in a horse.

What Causes Rain Rot?

  • While it can occur at any time during the year, it generally proliferates in high heat and humidity.
  • Dense winter coats also provide ideal conditions for dew poisoning.
  • I have also found that waterproof bug sprays lock moisture to the skin, which can exacerbate rain rot infections.
  • Just like with other bacterial infections (e.g., pink eye), the horse can reinfect himself from other areas of his skin.

Best Treatment for Rain Rot

The single best way I have found to treat rain rot is to use an antibacterial shampoo (containing chlorhexidine, betadine, or benzoyl peroxide) or antifungal shampoo (containing 1-2% miconazole) in the following way:

  • Rinse your animal thoroughly.
  • With a gloved hand and medicated soap, feel for and remove all scabs. Generally, you will find pink, inflamed skin behind those scabs. Scab removal has been shown to increase healing times.
  • Make sure to look behind the legs, around the ankles, and on the insides of the legs.
  • If your animal has a thick coat, you may need to clip hair away from infected areas to better reach scabs.
  • Let the shampoo sit on your animal for 10 minutes.
  • Remove and throw away your used gloves.
  • Rinse your animal.
  • Then, wash your animal a second time.
  • Again, feel for scabs. (If you did a good job the first time, you shouldn’t find any more scabs).
  • Rinse and be sure all shampoo is removed.
  • Allow your animal to dry and apply medication to the affected areas.

Most of the products for treating rain rot recommend doing a double wash. I have done single washes before but found that the double wash makes the problem go away much quicker.

Best Products I've Used to Treat Rain Rot

The following products have been shown to dramatically improve healing time in my horses:

  • Cowboy Magic Shampoo
  • Cowboy Magic Krud Buster (spray on after bathing)
  • Vetracyn (apply after bathing)
  • Iodine-based shampoos
  • Colloidal Silver Spray (apply after bathing; works great as a “liquid bandage")

Check your animal daily for reoccurrence, and repeat the treatment method above, if necessary. Depending on the severity, it may take a few weeks to heal, but it always goes away.

For dogs and cats, you may want to try the following highly regarded antibacterial and antifungal shampoos:

  • Davis Miconazole Pet Shampoo
  • Davis Benzoyl Peroxide Medicated Dog & Cat Shampoo
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Read More From Pethelpful

How to Detect Rain Rot in Its Early Stages

To detect rain rot in its early stages, it is best to check your animals daily.

  • I run my hands along each leg, paying particular attention to the ankles, joints, and underarms.
  • If your animal has a tail that lays against the skin, be sure to check there as well.
  • Be sure to check the face, neck, and under the chin.
  • Floppy ears on dogs can also be a common location.
  • When you find rain rot, it will feel like a scab. This scab should be removed because scabs prevent healing. The bacteria that cause this skin infection are anaerobic (they do not like oxygen), so they form scabs for protection.

Preventing Rain Rot

It is extremely difficult to prevent the spread of rain rot unless it is caught very early.

  • If your animal has this condition or has had it in the recent past, do not share items that come into contact with the infected skin.
  • For horses, this means brushes, leg wraps, saddle pads, girths, breast collars, or anything else that can come into contact with the skin of other horses.
  • Wash all fabric items with hot water.
  • Neoprene can be cleaned with a dilute solution of chlorine.
  • As a general rule, each of my horses has his/her own set of brushes, saddle pads, girths, and breast collars. This helps prevent the spread of disease.
  • In inclement weather, keep horses in barns, away from mud, ensure their bedding is always dry, and fill in muddy holes near gates.
  • Each dog should also have its own collar, bedding, kennel, etc.
  • In addition, good nutrition helps support a healthy immune system. Consult a nutritionist or veterinarian to ensure your animal is getting what he needs.
  • Finally, it is possible to transfer rain rot to your own skin and, therefore, to your other pets. Be careful and wash your hands thoroughly after treatment.


This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.


Teresa on May 29, 2018:

Washed my dog a couple weeks ago, she has a very thick coat. Currently in rainy season and today detected hard spots in her coat. I thought the firm might’ve been mad it but it wasn’t mad at there the day before. When I tried to see what was the issue under her for the for actually lifted away from her skin leaving a bald spot. It appeared pussy underneath so obviously an infection. I’m assuming this is similar to rain rot as I have seen on horses. I plan to use the same method as removing it on horses and hoping for good results on February 21, 2018:

Are there home remedies? I have very little cash to spend and she is a Siberian Husky ..

Shelley Ferraro on October 26, 2017:

My horse is getting it now in the fall.

Mardi Winder-Adams from Western Canada and Texas on February 02, 2012:

Great article. I am lucky our horses have never had rain rot but it can be a problem here in Texas in wet winters. It seems that horses that are in poor condition run a greater risk of developing the condition?

Thanks also for mentioning Vetracyn - that is a must have in your home horse first aid kit!

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