How Do I Know if My Dog Has Ringworm? Symptoms and Treatment

Although it's often assumed that ringworm is caused by a worm, the culprit behind this infection is actually always a fungus. Ringworm is found all over the world and affects all kinds of animals, including our dogs, and even humans.

In this Soyunperro article, we'll find out exactly what this infection is, how it spreads, and what its main symptoms are, so we can recognize them and act quickly.

We'll also cover how ringworm is diagnosed in dogs and the most common treatments specialists recommend to get rid of it, preventing the fungus from spreading to other family members. Ready to dive in? Let's go.

What Is Canine Ringworm?

Ringworm is a fungal condition caused by the fungus Microsporum canis. It's a highly contagious infection that can spread through direct contact between an infected animal and a non-infected one, or through grooming tools, bedding, collars, ectoparasites, and/or exposure to a contaminated environment.

Microsporum canis infections generally come from contact with an infected animal, mainly cats. Humans can also develop these fungal infections.

In our furry friends, ringworm can also be caused by Microsporum gypseum and Trichophyton mentagrophytes. Most Trichophyton infections are believed to come from contact with infected rodents or their nests.

These organisms live and reproduce on the skin and in hair follicles, where hair grows. The dogs most vulnerable to ringworm are puppies, older dogs, and those with a weakened immune system due to illness.

How Does Ringworm Spread to Dogs and Humans?

Ringworm is transmitted in dogs through direct contact with the fungus. So, if a dog touches an object or comes into contact with an infected animal or person, it can become infected.

It spreads through ringworm fungal spores, which are usually present in shed hairs and can survive on a sofa, a comb, a food bowl, or clothing for up to 18 months.

Because of this, it's important to take every possible precaution to prevent it from spreading. Humans can also become infected with Microsporum canis, with babies, the elderly, and people with health problems at greater risk.

The most notable symptoms on human skin can include a circular, raised, red-patched rash, which can also affect the hair. It may start as a pimple-like bump before spreading to a larger area, causing patchy hair loss, while nails become discolored, turning white or yellowish, thick, and even brittle.

Five Symptoms of Ringworm in Dogs

Ringworm in dogs isn't fatal, but it is very contagious. That's why it's important to know its symptoms well, so that if detected, a vet can start treating the dog right away.

This will help us prevent other dogs or people from being affected. The five most common symptoms of ringworm in dogs are:

• Brittle, dry hair.
• Fragile, rough nails.
• Yellowish, foul-smelling scabs and scales.
• Changes in the skin's appearance or inflammation.
• Circular lesions accompanied by hair loss (alopecia).

In fact, these lesions or patches are one of the most telling signs of ringworm in dogs. They typically start healing from the center, and scabs can appear when they become inflamed. Contrary to popular belief, ringworm doesn't itch.

If your dog shows these signs, don't hesitate — take it to the vet for an exam so they can confirm whether it's ringworm or another fungal or skin condition, which could be related to nutritional deficiencies, allergies, canine hypothyroidism, or Cushing's Syndrome.

What Factors Make Your Dog More Likely to Get the Disease?

Although contact with the fungi mentioned above is the main cause of infection, other factors can further increase the risk of ringworm.

• Breeds such as Yorkshire Terriers, German Shorthaired Pointers, Fox Terriers, Labrador Retrievers, Belgian Shepherd Groenendaels, Beagles, Jack Russell Terriers, German Shepherds, and Jagdterriers are especially prone to the disease.
• Conditions such as hyperadrenocorticism, or certain treatments — mainly corticosteroid therapy — can encourage the appearance and worsening of fungal lesions by weakening immunity.
• Pre-existing moist dermatitis also creates ideal conditions for fungal spores to take hold.

Diagnosis and Treatment of Ringworm in Dogs

When we take the dog to the vet, they'll examine the lesions and can take samples from the circular patches to reach a diagnosis. A definitive diagnosis is made through a fungal culture, to correctly determine the therapy to follow.

If ringworm is confirmed in the dog, the specialist will decide on the most suitable treatment, taking into account how severe the infection is and the dog's overall health.

The vet plays an extremely important role in controlling and preventing the disease, since, given its high zoonotic potential, it's essential to confirm the infection quickly in animals and establish the appropriate treatment, limiting environmental contamination and the spread to other animals or humans.

Depending on how severe the lesions are, treatment may involve antifungal ointments alone, or combined with oral treatment.

And remember: it's very important to thoroughly disinfect your furry companion's entire environment and stick with the ringworm treatment until the end, even once the signs on the dog have seemingly "disappeared." Conidia (fungal structures) are very resistant and can remain viable in the environment for years. This reduces the chances of the fungal infection resurfacing just when we thought we'd won the battle.