Treating Rain Rot in Horses That Live Outside

An equine dermatology expert describes what causes rain rot in horses and how you can prevent and manage it in horses on full-time turnout.

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rain rot
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Rain rot is mainly caused by moisture, which can be hard to avoid for horses that live on pasture. Rosanna Marsella, DVM, Dipl. ACVD, of the University of Florida, in Gainesville, explains how you can combat the effects of excess moisture in your horse’s environment to effectively manage and prevent rain rot.

This podcast is an excerpt of our Ask TheHorse Live Q&A, “Navigating Skin Problems in Horses.” Listen to the full recording here.

About the Expert

Dr. Rosanna Marsella

Rosanna Marsella, DVM, Dipl. ACVD

Dr. Marsella is a veterinary dermatologist and a full Professor at the University of Florida, College of Veterinary Medicine. Dr. Marsella has a special interest in equine dermatology. She has led the International Committee which has published the Clinical Consensus Guidelines on Equine Allergic Skin Diseases published in 2023. She has also authored a book on equine dermatology which is geared toward equine clinicians that have a special interest in dermatology. She has devoted the last few years working on mechanisms of pruritus in horses and has worked on the identification of alternative treatments to provide relief to itchy horses. She has also tested topical bacteriophages for the treatment of equine pyoderma in the attempt to identify antibiotic free alternative treatments for equine infections. She has published on the trends of antibiotic resistance at her referral institution, the University of Florida. Dr. Marsella is an avid equestrian, rider and owner.


Written by:

Haylie Kerstetter, Digital Editor, holds a degree in equine studies with a concentration in communications and a minor in social media marketing. She is a Pennsylvania native and, as a horse owner herself, has a passion for helping owners provide the best care for their horses. When she is not writing or in the barn, she is spending time with her dog, Clementine.

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