Ringworm in Dogs

Ringworm is a fairly common skin infection in dogs, yet despite its name, no actual worm is involved. Instead, a fungus targets the skin, coat, and sometimes even the nails. Because the infection is contagious, it can pass to other animals – and even to people – and often shows up as round, hair-free patches on your dog’s body.

Spotting ringworm early allows you to start treatment quickly and keep the fungus from spreading. In this article, you’ll learn what ringworm is, how dogs catch it, and the signs worth watching. You’ll also find out how vets confirm a diagnosis, which treatments work best, what you can do at home, and when to pick up the phone and call your vet.

What Is Ringworm?

Ringworm (also called dermatophytosis) develops when certain fungi settle on the surface of the skin. In dogs, the most common culprit is Microsporum canis. The fungus feeds on keratin, the protein that forms skin, fur, and nails, which explains the flaky skin and patchy hair loss that often follow.

Because ringworm can spread to people and other pets, acting quickly protects the entire household.

Causes and Risk Factors

Most dogs pick up ringworm through direct contact with an infected animal, but the spores can also spread through brushes, bedding, or furniture. Certain situations also make infection more likely:

• Puppies and senior dogs have weaker immune systems.
• Humid environments give fungi an easy foothold.
• Shelters and boarding facilities pack many dogs into close quarters.
• Poor hygiene or crowded living conditions raise the overall risk.

Knowing these factors helps you see why some dogs run into trouble while others remain fungus-free.

Signs and Symptoms

Ringworm usually appears as patchy, circular areas of hair loss, yet that’s only part of the picture. Keep an eye out for:

• Red or scaly skin in affected spots
• Dry, crusty, or flaky patches
• Itching or scratching
• Brittle or discolored nails when the infection reaches the nail beds

These signs can mimic mange, allergies, or other skin problems, so a diagnosis from your vet is essential before beginning treatment.

How Ringworm Spreads

Once spores land in the environment, they’re remarkably resilient. A dog can become infected by touching a contaminated blanket, sharing a grooming tool, or simply playing in a park where another infected dog recently visited.

Spores can survive for months on porous surfaces such as carpets and fabric, which is why cleaning matters just as much as medication.

Diagnosis by a Veterinarian

If you think your pet might have ringworm, visit your vet as soon as possible. To diagnose ringworm, your vet may use a Wood’s lamp, an ultraviolet light that makes certain fungi glow. They may also take skin scrapings or hair samples to look at under a microscope.

A fungal culture is the most reliable diagnostic test, although it takes time to grow. Many clinics also offer PCR tests that detect fungal DNA within a day or two.

Remember, a clear diagnosis is key to effective treatment, so make sure to have your pet properly evaluated by a veterinarian.

Treatment Options

Treatment for ringworm depends on how far the infection has spread. Small, isolated spots often clear with antifungal creams, ointments, or medicated shampoos. Widespread cases may need oral antifungal medication, and dogs with long coats or numerous lesions can benefit from medicated dips or baths.

No matter which medication your vet chooses, make sure your dog finishes the entire course. Stopping treatment too soon allows stubborn spores to survive and cause the infection to return.

Home Care and Environmental Cleaning

Unfortunately, medication alone won’t solve the problem if spores remain in your home. That's why it's so important to wash bedding, soft toys, and towels in hot water, then dry them on high heat.

Clean hard surfaces with a diluted bleach solution, and vacuum carpets and upholstery daily. Make sure to empty or clean the vacuum after each use to prevent spores from spreading.

If you have other pets, keep them separated until your vet confirms the infection is gone. Thorough, routine cleaning supports the medical treatment and helps prevent a comeback.

Prevention Tips for Pet Parents

Preventing ringworm comes down to practicing good hygiene and staying alert. Here are a few simple tips to keep it at bay:

• Keep living spaces clean. Wash and disinfect bedding, toys, bowls, and grooming tools regularly.
• Isolate new or sick animals. Have newcomers examined by a vet before they mix with resident pets.
• Practice handwashing. Clean your hands after handling pets and avoid sharing towels or blankets.
• Groom and inspect often. Brushing exposes the skin, making it easier to catch symptoms early.
• Act quickly at the first sign. Circular hair loss or flaky skin deserves an immediate veterinary check.

When to Contact Your Vet

Reach out to your vet if you see bald spots, crusty skin, or other signs of irritation. Acting quickly can speed up recovery and stop the infection from spreading.

It's also important to follow up with your vet if the treatment isn’t working, the infection gets worse, or if another pet or person shows similar skin problems. Taking quick action can help keep your pets and family safe and healthy.

Ready to Protect Your Dog from Ringworm?

With proper veterinary care and consistent home cleaning, most dogs overcome ringworm and return to their usual, tail-wagging selves. If you suspect an infection, schedule an appointment, follow your vet’s guidance closely, and your dog will soon be back to feeling (and looking) their best.