Rain Rot Cover WHAT IS IT? The bacterium that causes rainrot, Dermatophilus congolensis, normally lives on the skin with no adverse effects. However, when a horse with conditions such as a compromised immune system, a weakened/damaged skin barrier, poor nutrition, poor hygiene, or a stressful situation is exposed to wet, moist conditions the door to rain rot is opened. These conditions, both external and internal, can allow the bacteria to multiply and irritate hair follicles, leading to painful crusting and hair loss on the top of the rump and along “runoff” lines of the flanks. Rain rot can be mild at first

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But if left untreated can grow into a serious problem

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Rain Rot is more common in the Spring and Summer when rains and warmer temperatures provide a fertile environment for this bacteria. However, it may crop up in winter if temperatures rise and fall causing some horses to sweat under their blankets again, creating a warm, moist environment for the bacteria to grow.

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It is suggested that the source of dermatophilus congolensis is the soil, where such organisms contribute to the breakdown of organic matter. It is also thought to exist, dormant, on an animal until the climate is favorable.

Warm moist climates create frequent recurrence of rain rot if susceptible horses cannot escape the wet weather. Moisture is trapped under the hair allowing fungus or bacteria to grow on the skin. Horses with sensitive skin may over-react to fly bites causing persistent itching, which in turn may lead to further damage from the horse rubbing himself raw thus increasing the chances for any infection.

It's important to note that previously infected horses do not necessarily develop immunity to re-infection of rain rot.


Grooming: A daily grooming session or at least a peek under the blankets is necessary to notice these changes. A course of anti-biotics at the earliest stages can head off rainrot, so consider calling your veterinarian if you see signs of the condition.

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Tack: Expose tack (especially the parts that contact the horse) to the sun to help kill fungus. Wash tack after use. Dry tack properly and keep dry to avoid mold, and store it in a setting that allows for proper air circulation.

Farm Maintenance Practices: Skin damage and moisture are the two most important surface factors for the development of rain rot. Skin damage can come from a simple irritation or a small skin breach made by thorny plants or biting flies so utilize practices that reduce exposure to rain, injury, bugs and their biting and stress.

Shelter provides a dry area for the horse to get out of wet weather. Along with good health, it is the best defense against rain rot!

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Mud management is a must!


Rugs/fly sheets should be used during fly biting season over the body and neck. There are even special fly boots for severe needs for leg protection. A rain sheet in wet weather can help keep your horse dry.

Turnout. Sunshine is an important support for skin diseases, and helps kill fungus. If the animal is stalled, allow a minimum of 1 hour in the sun.

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Insect repelling plants can be planted near and around the barn and shelters. Include tansy, garlic, lavender, rue, citronella, scented geraniums, and wormwood.

Manure removal and covered compost heaps help discourage fly breeding.

Pasture rotation reduces parasite exposure and muddy areas.

Support the immune system with proper nutrition and health. The healthier the horse the better chance they can deal with it themselves.


Rainrot is more likely to strike older or immune-compromised horses so work with your vet with these delicate animals.


Treatment must be multi-faceted and include the inside and outside of the horse! Feed to Support Immune System- a healthy diet filled with plenty of antioxidants and immune boosting nutrients. Reduce Stress- stress lowers the immune systems ability to fight infection. Keep Dry- A run-in, rain sheets and/or stabling reduces stress and exposure. Depositphotos_1106139_m Use Topical Treatments and Washes. Here are some ideas I gathered from various discussion boards. The list includes products that seem to be the most popular; prepared, home remedies, and some all natural options too. Note: I have not tried all of these and am not recommending any product over others, this is for informational purposes only. Over-The-Counter Products: Banixx™ (www.banixx.com) MTG: (www.shapleys.com) Make Your Own:
  • My Home Remedy: I combined a tube of triple antibiotic ointment, hydrocortizone 1% onintment, and nystatin fungal ointment - all found in your local drug store. Combine all three and stir to make a paste. The antibiotic ointment fights infection, hydrocortizone ointment stops the irritation and itch, and the fungal ointment fights the fungus. Apply the paste to the areas after washing with betadine scrub. Leave the paste on. It reduces the irritation, stops the itching, and reduces fly attraction. Repeat the process the next day. After one to two applications, you could see the difference, the irritation and oozing stopped. If you have a bad case, once the sores have crusted, sprinkle on Goldbond foot powder. In about a week, you will see new hair growth.
  • Gold Bond Powder Athlete’s foot-Groom off the scabs that are ready to fall off then apply the powder.
  • Listerine (not the generics -- the formula is different) in a spray bottle. Spray it on, let it dry, then rinse with warm water.
  • Listerine and baby oil. Use equal parts and rub the concoction onto the affected areas . Note: Listerine contains alcohol, which can irritate your horse's skin. The organism that causes rain rot is taking advantage of the fact that waterlogged skin is immune-compromised, and irritating that skin can make it even more vulnerable to infection.
  • A milder concoction-Mix a 16-ounce bottle of mineral oil, a 16-ounce bottle of 3 percent USP hydrogen peroxide, and a half-ounce bottle of tincture of iodine in a bucket. Sponge it on the affected areas and let it set overnight. This will soften and lift the scabs, soothe and lubricate the skin, and kill the bug. Next day, shampoo your horse with a mild shampoo and let the area air-dry, preferably in the sun. NOTE: Don't put this concoction in a sealed container. It'll bubble up and explode.

The NATURAL Alternative: (well you know I prefer these)

Prepared OTC products:

  • Calm Coat: (www.calmcoat.com)
  • Muck Itch Skin Saver- (www.muckitch.com)
  • Rea Tree oil (www.healing-tree.com/Tea-Clenz.html)
  • Pete's Equine Remedy (www.ffrogworks.com)
  • Equi-Derm-herb powder supplement (chickweed, plantain, yellow dock) for cleansing, purifying, detoxing, to help the body heal rain rot from within (www.rivasremedies.com)
  • Natural Antibacterial Healing Spray ( www.espree.com)
  • Grape Balm Herbal Wound Healer (www.thenaturalhorsevet.net)

Make your own:

  • 10ml aloe vera gel as a base, 10 drops each of Patchouli, Frankincense, Myrrh, and Yarrow, Blend in 5ml of linseed oil. Add Chamomile tea gradually (up to 100ml) until there are no separations. Store out of direct light and extreme cold in a jar or bottle for up to 1 year.

I hope this helps you tackle this frustrating issue! Please feel free to leave a comment about your success with these treatments or others you have tried.

If you would like a gussied-up PDF version of this article to download CLICK HERE

Til we meet again….


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