Rain Rot in Horses

Rain Rot in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

Most common symptoms


Rated as serious conditon

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Most common symptoms

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Rain Rot in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

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What is Rain Rot?

Rain rot can develop on a horse where water stands for long periods of time, such as his back. If he is out in the pasture with no protection against the rain and it rains for days at a time, the bacteria known as Dermatophilus congolensis takes advantage of the opportunity. It will get into your horse’s skin, cause crusty scabbing on the hair and skin, and possibly even a secondary skin infection. If the region is small and you are comfortable attempting to treat it on your own, you can. However, if you are unsure, or if it is affecting a large region, it is recommended you seek veterinary care. Without proper treatment, the rain rot will spread and only worsen.

If you live in a wet environment where your horse is unable to dry out between storms, he is likely to develop a condition known as rain rot. You can try and treat it yourself, but consulting with your veterinarian for a treatment plan is best.

Symptoms of Rain Rot in Horses

Symptoms typically affect the skin where moisture accumulates. Symptoms may include:

  • Hair standing on end
  • Thick crusted skin
  • Matted hair
  • Warm skin
  • Painful to the touch
  • Affected hair and skin can be peeled away easily
  • Raw, sensitive areas can be found under the affected, crusted skin


Rain rot is most commonly associated with wet, rainy environments where your horse is wet for long periods of time without the chance to dry out. No matter where on your horse’s body the rain rot appears, it is all caused by the same organism. Rain rot can also be known by the term rain scald.

Causes of Rain Rot in Horses

Rain rot is caused by the bacterial organism known as Dermatophilus congolensis and most commonly causes problems in wet climates. Rain rot typically develops in areas where skin has been damaged by insects, trauma, or chronic moisture. An area where moisture accumulates, such as the top of your horse’s hindquarters or back, is typically where symptoms occur.

Diagnosis of Rain Rot in Horses

Your veterinarian will want to perform a full physical exam on your horse to check for other areas of rain rot development. It is likely she will be able to diagnose what he is experiencing just by appearance alone. For exact diagnostics, she will collect a sample of crust and hair from the affected region to send out to a diagnostic laboratory. The lab will be able to confirm the exact organism causing the symptoms in your horse. 

Your veterinarian may also want to perform blood work to check organ function and severity of the infection. A complete blood count and chemistry panel will offer the necessary information to allow your veterinarian to determine if your horse needs additional therapies.


Treatment of Rain Rot in Horses

The severity of your horse’s rain rot condition will determine his course of treatment. Grooming of the area to remove crusts and hair is very important. Shampooing the area with a medicated shampoo is also helpful. A chlorhexidine or benzoyl peroxide shampoo is ideal when cleaning the area. Shampooing should be repeated daily for 5 to 7 days and then as periodically until the condition resolves. In most cases, application of topical medications to the affected area in addition to the grooming and shampooing is enough. 

It should be noted that you need to dispose of the crusted skin and hair properly in order to prevent bacterial contamination of the area and prevent the spread of it to other horses. You should also soak the brushes you use on the affected horse in bleach in order to prevent passing the infection on to another horse.

In more severe cases of infection, your horse may also need systemic antibiotics. Oral medications or injectable medication may be appropriate options for your horse’s condition.

Recovery of Rain Rot in Horses

Once proper treatment is started, the rain rot will resolve and your horse should not suffer any long term consequences. If you do not begin treatment as soon as possible, it will spread and only get worse.

Naturally, prevention of rain rot development is ideal. In cases where you live in a rainy climate and your horse is turned out for extended periods of time, you may want to consider putting a rain sheet or other waterproof blanket on him. This will keep water from accumulating and settling directly on his back and hindquarters. If your horse is out in the pasture without protection against the rain, you should check him periodically to ensure he is not developing rain rot.

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Rain Rot Average Cost

From 319 quotes ranging from $650 - $1,200

Average Cost


Rain Rot Questions and Advice from Veterinary Professionals






15 Years


Serious condition


0 found helpful


Serious condition

Has Symptoms

Lesions And Peeling Skin

we have a horse with severe rain rot, is there a shot I could buy and give him? We have tried several topical treatments and nothing is working. He gets dexamethazone daily due to heaves, and I was wondering if this could be preventing his infection from healing. He has lost weight and looks so pityful.

March 5, 2018

Merlin's Owner


Dr. Michele K. DVM


1611 Recommendations

Thank you for your email. Without seeing Merlin, I cannot diagnose him or recommend anything to treat his condition. Since he seems to be suffering, it would be best to have your veterinarian look at him, as they can determine what is going on and how best to treat him.

March 6, 2018

Rain Rot Average Cost

From 319 quotes ranging from $650 - $1,200

Average Cost