Only a licensed veterinarian can definitively diagnose ringworm in your pet or feral cats. The most reliable way a veterinarian uses to diagnose ringworm is by sending samples to a lab, but that can take a couple of weeks. Faster, less accurate ways exist, such as using a UV lamp to check for glowing strands of hair (this occurs about half of the time in ringworm infections) or by looking at skin scrapings under a microscope.
That said, if you have a lot of experience with cat colonies, kitten fostering, and animal rescue and animal shelters, then you might be able to make an educated guess based on experience.
Treatment for Ringworm in Cats
Here’s some good news: Ringworm SOUNDS scary but it really isn’t! Ringworm is usually mild and self-limiting in adult cats. That means it’s a minor issue and will often resolve on its own. Most adult cats and humans are often resistant to infection so the chances of you catching ringworm from your infected cat is very low, even if you weren’t being careful. And if you or your cat do catch ringworm, it’s super easy to treat. It just takes time.
Sometimes no treatment is necessary. Most mild ringworm infections in cats will heal on their own due to a cat’s immune system. That’s excellent news for us feral cat caretakers! I don’t bring in my barn cats or cat colony for ringworm unless it is making the cat miserable or it is severe or persistent. The trauma of treating an unsocialized cat for ringworm and bringing him into the vet is more harmful than the ringworm infection itself.
That said, treating your pets and yourself can help reduce the length of infection and help stop it from spreading to other animals. And ALWAYS treat kittens who are infected. They do not have strong immune systems.
It is always best to isolate the infected cat from others to help stop the spread of ringworm, if possible. The environment (i.e. the house) must also be treated if you want to completely cure the infection.
The most common way to treat ringworm is to use topical antifungal medications. This may include creams, medicated antifungal shampoos, or a lime sulfur dip. Or a combination of all of these. Always follow your veterinarian’s instructions.
If the cat is a long-haired variety, your vet may suggest clipping the fur to help make treating the cat easier.
For more severe infections, your veterinarian may prescribe an oral antifungal medication as well as those topical options listed above. (I have included examples in the links, but what your vet recommends might be different!)