Ringworm in Dogs: Causes, Symptoms & Treatments

If you’re not familiar with ringworm in dogs, the name can be misleading. Ringworm isn’t actually a worm.

Rather, it’s a highly contagious fungal infection that can affect almost everyone from humans to domesticated animals. Unfortunately, there is no natural immunity to the fungus. Even physically and mentally fit dogs who eat a diet of healthy dog food can catch it.

Ringworm can spread quickly, so it’s important to know the signs of infection and understand how you can stop it from affecting yourself and others.

What Is Ringworm in Dogs?

Ringworm is caused by a fungus called a dermatophyte that grows on the outer layer of skin, invading the skin, hair follicles and nails. It mainly affects areas on the body such as the face, ear tips, tail, paws and bellies. Puppies, seniors and those with weakened immune systems may see more widespread infections.

How Does Ringworm Spread?

Ringworm is mainly spread by direct contact with infected animals but can also be transmitted by contact with contaminated objects, ranging from a food bowl to the carpet.

Fungal spores can survive in the environment, including on all household surfaces and upholstery, for up to almost two years. A ringworm-infected dog may also shed fungal spores and infected hairs around the house.

Factors That Affect Spread

Remember to take precautions, but also know your dog’s infection won’t necessarily spread to the other people and pets in your household. Contact with the fungus is more likely to result in infection if there is damage to the skin already. Other factors such as health and age can play a role as well.

It may take several weeks for a host to develop immunity and infection to wane.

Symptoms of Ringworm in Dogs

If your dog has ringworm, you may see some or all the following signs:

• Red patches of raised, crusty skin (often, but not always, circular in shape)
• Alopecia (fur loss)
• Dandruff or scaly skin
• Itchy skin

Diagnosing Ringworm in Dogs

If you think your dog has ringworm, take them to your veterinarian for diagnosis as soon as possible. Prompt treatment will help stop the spread to other pets in your home and your family.

When checking your dog for ringworm, your veterinarian may:

• Examine your pet under an ultraviolet (UV) lamp. For some types of ringworm, infected hair and skin will turn green when exposed to UV light.
• Review a sample of your dog’s fur under a microscope to look for evidence of the fungus.
• Do a fungal culture. If the fungus isn’t clearly seen under the microscope, your veterinarian may take the sample and put it in a dish to see if it will grow in lab conditions. This is one of the most reliable methods of diagnosis but results can take up to 10 days.

If you have a suspected ringworm case in your home, you should also check all family members and other pets to ensure it has not spread to them. Anyone who’s been infected will require treatment.

Ringworm Treatment for Dogs

While ringworm can clear up on its own, treating an infected pet will likely speed up recovery and reduce the risk of spread to others.

Ringworm treatment for dogs typically includes medication. The type of medication will depend on the variety of ringworm causing the infection.

Prescriptions may include oral medications to prevent the fungus from reproducing, or topical solutions such as a lotion or shampoo. A combination of medications and topical solutions might also be required for effective treatment.

How Can I Stop Ringworm From Spreading?

Because ringworm is contagious, consider quarantining your infected dog in one room of the home until you speak to your veterinarian. If possible, avoid touching your pet. If contact is necessary, however, wear disposable gloves and wash your skin and clothes afterwards.

You’ll also need to eliminate ringworm spores throughout your home. Spores can still spread the fungus, even after your dog is free of infection.

Thoroughly vacuum surfaces and upholstery; steam cleaning is also a good idea. Bedding and towels should be washed, and hard surfaces will require disinfecting (ask your veterinarian for recommendations for effective, pet-safe disinfectants).

Learn more health tips for your dog from our pet experts. You can also visit our Pet Expertise page.