Treatment for Ringworm

Q. I have consulted with three local veterinarians about the best way to treat ringworm. Each one gave me a different treatment recommendation. What is the most effective way to treat ringworm?


A. Ringworm, which is not actually a worm but a fungal infection, is most likely a normal inhabitant of the skin. It can be introduced into the skin through abrasions or inflammation to create the crusty, flaky, round, hairless areas that are typically associated with the disease. There are many treatment options, which is why you have received the variety of recommendations. Your veterinarian will make a treatment plan that is most likely going to be safe and effective for your horse and also fit into your management situation.

Usually, the first part of treatment is to remove as much loose hair and crust as possible. This will decrease the number of fungal elements available that can re-infect the skin and spread to other objects, such as brushes, saddle pads, and blankets. Povidone iodine, used in frequent daily treatments, is a common agent used to disinfect the surface of the skin. Other agents may include chlorhexidine (Nolvasan), diluted bleach (watch out for irritation), and anti-fungal shampoos. In some cases, this may be all that is needed.

It takes several weeks to kill all of the fungal organisms, as they are living deep in the hair follicle. It is also important to disinfect grooming equipment and tack with povidone iodine or bleach to decrease the spread of the organism.

Some stubborn cases will benefit from treatment with a specific anti-fungal agent, such as gresiofulvin (Fulvacin), which can be added daily to the feed. In some cases it will be administered by your veterinarian in a bolus via a stomach tube. There are some health risks associated with gresiofulvin that include liver toxicity, so it is important to consider the general health of your horse before choosing the best treatment.

This can be a stubborn problem, so be diligent in the course and duration of treatment. There also can be an underlying cause for the ringworm infection, and a medical work-up, including a blood panel, might be needed. Working closely with your veterinarian will usually clear up the infection.

About the Author

Jeffrey T. Berk, VMD

Jeffrey T. Berk, VMD, is a partner in Ocala Equine Hospital in Ocala, Fla., and he is a Director-At-Large of the AAEP.

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