Rain Scald - A Seasonal Affliction for Horses

Palomino horses in spring pasture.
Palomino horses in spring pasture. Images

Newsdate: Tuesday, April 21, 2020 – 11:30 am
Location: GILROY, California

As temperatures rise and rainfall and other wet conditions develop in many areas, horses pastured or maintained in areas where the ground is often wet may develop the condition Dermatophilosis also known as rain scald.

Horse with rain scald patches on back.

Horse with rain scald patches on back

Horses pastured or maintained in areas where the ground is often wet may develop the condition Dermatophilosis also known as rain scald.
© 2016 by Zoom Team

While many horse owners think the bacteria that causes Dermatophilosis lives in the soil, it is actually carried on a horse's skin. Some horses become immune to the bacteria, but others are affected year after year, usually during a warm, wet season, although the condition can occur during wet winter weather.

Two conditions must be present for Dematophilosis to develop: 

  • Wet weather
  • A break in the skin of the horse

Rain scald is most prevalent in horses that are very young, very old, immunosuppressed or chronically exposed to moisture. Biting insects or infected tack, brushes or blankets may spread the infection from horse to horse.

The bacteria can live on damp fence posts, stall doors and other places where horses often rub themselves. If a horse is a carrier of the dermatophilosis bacteria, another horse rubbing itself in the same spot may become infected if there is a break in the horse's skin.

Once the bacteria is under the skin of the horse, it produces thread-like tentacles that spread in many directions. The bacteria likes anaerobic conditions meaning that it thrives in an environment where the oxygen content is low or absent.

Once a horse contracts rain scald, the infection is responsive to a course of antibiotics, and topical agents work well on infected areas. Infected areas should be clipped out, and scabs softened and lifted off. If scabs are not easily removed, soak or shampoo until they soften and can be gently removed with a soft brush.

The best method of prevention of rain scald is keeping horses in dry conditions whenever possible including making sure stalls and bedding are dry. Careful grooming on a daily basis will also help prevent rain scald if attention is paid to any breaks in the horse's skin or any signs that an infection has occurred.

About the Author

Flossie Sellers

Author picture

As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere.

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