How to Treat Rain Rot in Horses

by Caitlyn Andrews April 17, 2019

equine rain rot treat and prevent

It's spring and that means April showers are here. It's warming up outside and the horses are out enjoying the break from the long winter.

It might feel nice out, but spring weather is ideal for a pesky skin condition called rain rot. Standing out in the rain is one of the most common ways for a horse to get rain rot, but it's not the only way.

This post will help you:

  • prevent rain rot
  • watch for the signs
  • treat the condition

What is rain rot in horses?

Rain rot, also known as rain scald, is a bacterial infection of the skin. It's often mistaken for a fungal disease like ringworm. Antifungal meds have no effect on this bacterial condition and should not be used to treat rain rot. 

Rain rot is sometimes called dew poisoning. While they're caused by the same bacteria, dew poisoning and rain rot appear on different parts of the body. Rain rot is typically located on the back, head, and neck. Dew poisoning occurs on the pasterns.

If your horse has rain rot you'll see crusty scabs that expose smooth, bare skin when picked off. Lesions are often itchy or even painful. Your vet can diagnose rain rot with a visual check, but they can also take a skin scraping to get a firm diagnosis.

The bacteria that causes rain rot spreads through the skin layers causing pustules, or pus-filled bumps, to form. The skin layer beneath these bumps will die off and stick to the hair. This is what creates the clumps that you pull off.

Healthy skin acts as a natural barrier to protect against bacteria. When the skin is broken by bug bites, cuts, or sores then it can't fend off the bacteria. Excess moisture causes a similar problem. When the coat stays wet the protective oils in the skin are removed and bacteria can get in. This is why rain rot is so common in the spring when wet weather and biting insects arrive.

horse outside in the rain

Horses left out in wet weather can get rain rot, but it's not the only way to get this skin condition.

How do horses get rain rot?

Any horse can get rain rot. No matter their age, health, or location.

It's a myth that only horses stuck in the rain without a blanket will get this skin condition, though this is the most common way. Rain rot does best in warm, wet weather. When the skin is saturated or broken by bugs or cuts, the bacteria can get in.

Simply pulling the scabs off or brushing your horse out does not treat the bacteria. Not treating the initial outbreak of rain rot can allow the bacteria to spread and continue to be a problem for your horse. This leads to another way that horses can get rain rot - other horses.

Is rain rot contagious?

Yes. Rain rot can be spread from one horse to another. This is why it's important to not share brushes, blankets, or tack with a horse that has rain rot. 

It's best to give horses their own set of brushes and equipment whenever possible and clean them regularly.

How can I prevent rain rot?

Rain rot can be prevented by taking certain steps. Here are three of the top ways to prevent your horse from getting rain rot. 

1. Groom daily

Daily grooming is one of the best ways to prevent rain rot. Be sure to keep your horse's grooming tools separate from other horses. Clean the brushes often.

daily horse grooming prevents rain rot

Tip: If you have multiple horses, pick a color for each one and keep grooming tools in that color. Pick up a matching tote for each horse to keep the color-coordinated brushes separate from each other.

Grooming your horse keeps their coat and skin healthy. It also lets you keep an eye on their skin so you can spot conditions like rain rot early and treat them before they become a problem.

2. Reduce environmental factors

Providing shelter during rainy weather is great, but horses will often ignore a lean-to or shed. They would rather be out grazing in the rain. If the conditions outside are ideal for rain rot, then leave your horse in their stall when possible or use protective rain sheets.

3. Waterproof blankets each season

If you use blankets for your horses then this step is essential.

It's easy to forget about blanket maintenance, especially when the sheet doesn't look torn or damaged. However, seasons of use can wear out the weatherproofing on blankets.

Wash your blankets before the start of each season. Once they're clean they need to be re-proofed. Not waterproofing your blanket can let rain in, but re-proofing incorrectly can block the airflow or wicking properties. This traps the horse's body heat under the sheet and sets up ideal conditions for rain rot.

Your best course of action is to check with the blanket manufacturer for the correct way to re-proof your horse's sheet.

How do I treat rain rot?

As soon as you know your horse has rain rot it's time to treat it. Simply picking off the scabs won't stop the spread of the spores.

The sooner you treat the problem the less likely it is to turn into a bigger issue. Without treatment, rain rot can spread to new areas of the skin and to other horses. It can also turn into a secondary, more serious infection.

To treat rain rot, first, address the environmental factors:

  • Keep your horse out of the rain when possible
  • Provide shelter or keep your horse in a stall while they're healing
  • Use a fly spray or fly sheets to keep bugs from irritating the skin
  • Clean and wash tack and grooming equipment
  • Weatherproof or use a new blanket if the old blanket is trapping moisture
  • Take a break from riding if tack covers areas affected by rain rot

In some cases, rain rot will clear up on its own just by taking care of the environmental factors above. However, it's still best to treat the condition to make sure it doesn't return.

Using a curry to gently remove the scabs, bathe your horse with an antimicrobial shampoo. Rinse thoroughly and use a sweat scraper to remove the excess water.

If the condition is severe, your vet may want to start an antibiotic treatment. Consult with your veterinarian for treatment recommendations for your specific case.

Take preventative steps to avoid rain rot

When it comes to rain rot, prevention is the best treatment. If your horse does get rain rot then don't worry. Most cases are easy to treat using the tips above.

Caitlyn Andrews
Caitlyn Andrews


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