Veterinarian Reviewed on March 29, 2014 by Dr. Janice Huntingford
Although many people think canine ringworm is caused by a parasite thanks to the use of the word “worm,” it is actually caused by one of several varieties of fungi which cause a rash on a dog’s skin.
Signs and Symptoms
The signs and symptoms of canine ringworm are usually the same in all dogs, making it simple to identify and treat. A visual inspection is often all that is needed to determine the presence of the fungus, but it’s always best to confirm your suspicions with the help of your vet.
Your veterinarian will do one, or more, of three different tests to determine whether or not your dog truly does have ringworm:
Culture Test – Your Vet will collect a few skin cells and have them cultured. Whilst this test does take the longest, it is also the most effective.
Woods Test – This is simply the use of a black light with a magnifying lens attached. Roughly 50% of all ringworm fungus will be seen as being fluorescent under a black light.
Microscopic Test – Effective in about 40-70% of all ringworm cases, this test involves plucking a hair from your dog’s infected area and placing it in a specially formulated solution so that your Vet can view it under a microscope.
The most common sign of canine ringworm is a small, hairless, round shaped lesion on the dog’s skin. The inner portion of the lesion, which might start out as a small mark but continues to grow, will be scaly and small pustules may form.
The lesions caused by ringworm may be itchy, but not always, and the most common place you will see them are on the head followed by the legs, tails, or feet.
Treatment for Canine Ringworm
For small, isolated lesions in healthy dogs or puppies, treatment for canine ringworm may not even be necessary as it usually clears up on its own and heals fully after about four weeks. If treatment is in order, the infection should be treated twice per day with the use of a simple, antifungal medication applied directly to the skin which your vet can prescribe.
Some of the most common medications used include clotrimazole, ketoconazole, miconazole, terbinafine, or tolnaftate, and all of these often resolve the problem within a week or two. But, to prevent a recurrence, topical treatments should be continued for one more week after visible signs of the ringworm disappear.
Another option for getting rid of more severe cases of canine ringworm involves an oral antifungal medication, which must be obtained from a veterinarian who will prescribe the medicine and closely monitor treatment.
Oral medication for canine ringworm may be needed for several months, making it important for the dog to have regular checkups to ensure that toxic levels of the antifungal have not built up in their system.
There are also quite a few herbal formulations that can be applied directly to your dog’s skin to treat ringworm.
Preventing Canine Ringworm
Because the fungi responsible for ringworm thrive in warm, moist locations, it is important to take a proactive approach certain times of the year when it comes to preventing canine ringworm. Most cases of ringworm in dogs aren’t diagnosed until the fall or winter months and the condition is most prevalent in humid climates.
Canine ringworm can be transmitted very easily to other dogs as well as to humans if it is not controlled and treated properly. The spores causing the rash are often found thriving in the dog’s bedding.
Fungus spores can be shed out into the environment for as long as a year and a half, making it even more important to keep your pet’s cage and bedding clean as well as ensuring they are not infected with the fungus. Wash your pet’s bedding in hot water with a fungicidal soap on a regular basis.
Since ringworm can be transmitted to humans, avoid walking around barefoot and petting a dog that has bald spots as that is usually one of the first signs that they are carrying the fungus.
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Janice Huntingford, DVM, has been in veterinary practice for over 30 years and has founded two veterinary clinics since receiving her Doctor of Veterinary Medicine at the Ontario Veterinary College, University of Guelph. She has studied extensively in both conventional and holistic modalities. Ask Dr. Jan