How to Treat & Prevent Ringworm in Dogs
Many people are surprised to learn that ringworm in dogs is a skin condition caused by a fungus, not a worm—it's named for the ring-shaped, scaly sores it often causes. While that may lessen the gross-out factor, it doesn't make it any less of a problem. The fungal infection can get worse over time and is highly contagious. That's why it's important to seek treatment at an early stage when symptoms first appear.
What is Ringworm?
Ringworm is caused by a type of fungi called dermophytes. According to the Centers for Disease Control and Prevention, about 40 different kinds of dermophytes can cause ringworm. The fungi live and feed on the top layers of skin, hair, and nails.
Ringworm is more common in cats, but dogs can also catch it. Dogs get ringworm from coming into contact with infected animals, people, dirt, or surfaces like bedding, furniture, or grooming tools.
Signs Your Dog Has Ringworm
Ringworm doesn't infect every dog who's exposed to it. "Typically, it's hard for a ringworm infection to take hold in animals and humans with healthy skin and a robust immune system," Allison Brys, DVM, co-medical director of VCA Sawmill Animal Hospital in Columbus, Ohio, says. "But some factors can make dogs more vulnerable to ringworm."
Risk Factors for Ringworm in Dogs
- Age: Puppies and senior dogs have weaker immune systems that aren't as naturally resistant to fungi.
- Environment: Being in a group animal setting such as a shelter, pet store, or kennel increases a dog's chance of being exposed to infected animals.
- Medical conditions and medications: Some ongoing medical problems and medications can lower the immune system's ability to fight off germs.
- Behavior: Dogs that like to dig are more likely to come into contact with fungi spores (microscopic seeds) in the dirt.
- Breed: Boston terriers, Yorkshire terriers, and Jack Russell terriers are more susceptible to ringworm infection.
Symptoms of Ringworm in Dogs
Ringworm symptoms can take up to three weeks to develop after exposure. The most common places to spot ringworm infection are on a dog's face, ears, feet, and tail.
In the early stage of ringworm in dogs, there may be only one or two unusual spots. You may notice round hairless patches with pink, scaly sores. The sores aren't always circular and sometimes they look more like pimply bumps or may have a scab.
Typically, ringworm isn't itchy, but some dogs may scratch. Claws that break easily or become brittle and rough can be a sign of ringworm too. Without treatment, the infection may spread creating large areas of hair loss and scaly skin.
How to Treat Your Dog’s Ringworm
Eventually, ringworm usually goes away on its own. But during the months it takes to heal, it is possible to pass it on to other pets and people. Treatment speeds up recovery and minimizes the spread of infection, Brys says. Head to a vet if you see bald patches or sores on your dog.
To check for ringworm, vets frequently use a Wood's lamp (also known as a black light). Some types of ringworm glow green under its ultraviolet light, though it can still be possible your dog has ringworm if there's no glow. Your vet can also look at a hair sample or skin scraping from your dog under a microscope to confirm the presence of the fungus, or they may send it off to a lab for analysis.
Home Remedies for Ringworm in Dogs
If your dog has one or two ringworm sores, a home remedy could work, Brys says. Ask your vet if a topical ointment for athlete's foot might be an option. It should contain antifungal medication like clotrimazole (or another medication ending with 'zole').
Veterinary Treatment for Ringworm in Dogs
Oftentimes, vets treat ringworm with a combination of antifungal therapies. Your dog may need medicated ointments or shampoos as well as an oral medication like terbinafine, fluconazole, or griseofulvin.
The surest way to beat ringworm is to follow your vet's treatment plan, even if your dog's skin and fur look better. Treatment can last several weeks or months. If you stop too soon, ringworm will return. Your vet will test your dog at follow-up visits to see if ringworm is still present.
Remember, your pup will continue to be contagious for at least three weeks after starting aggressive treatment. It's important to separate your dog from areas where other pets and people are during the treatment period. Also, wear gloves and wash your hands every time you interact with your dog to avoid spreading it.
Can Humans Get Ringworm from Dogs?
Yes. Ringworm is a zoonotic disease, which means it can be passed among different animal species, like a cat to a dog, and to humans. The fungi that usually cause ringworm in dogs (microsporum canis, microsporum gypsum, and trichophyton mentagrophytes) are easily spread to others. You and your pets can get ringworm by direct contact with an infected pet, person, or contaminated surface.
How to Prevent Ringworm from Spreading
To prevent ringworm from spreading to other pets or reinfecting your dog, it's crucial that you disinfect your home. Ringworm spores are easily spread through shed hair and skin cells. They can live on surfaces for years unless you disinfect them. Areas that may be contaminated include:
- Grooming tools
- Food and water bowls
- Pet carrier and toys
Wash fabrics and sanitize surfaces with a diluted bleach solution wherever possible, Brys says. If you can't wash something (like your couch), go over it with a vacuum. Getting rid of ringworm spores is key to stopping its spread.
Also, dogs who spend a lot of time outdoors may need a medicated bath once or twice a week to prevent ringworm infection, Brys says. Ask your veterinarian what antifungal shampoos they recommend.
Ringworm takes effort to treat, but it is possible to battle the fungus successfully. And while you'll need to be vigilant about treating your pet's infection and disinfecting your home, your consistent hard work will be worth it in the end. Just remember: the fastest way to help your pet's skin clear up and stop ringworm from spreading is by following your vet's treatment plan, so be sure to give them a call if you suspect an infection or have questions about treatment.