Ringworm in dogs: Everything You Need to Know

Ringworm is one of those conditions that’s misleadingly named. Those unfamiliar with it would be justified in thinking a circular parasite of some sort has a role to play here, but no – ringworm is actually a fungal infection.

It’s a fairly common occurrence in the canine world, so it makes perfect sense for responsible pet parents to get clued up on ringworm, everything from the tell-tale signs and treatments to whether or not humans can suffer from the infection as well.

Read our guide and upgrade your ringworm knowledge in minutes by learning:

• Ringworm is a fungal infection
• Ringworm can affect your dog’s claws, hair and skin
• Common symptoms include hair loss, itchy skin and irritated-looking skin
• Humans can contract ringworm if they come into contact with an infected dog

Also known as dermatophytosis, ringworm is a rather nasty fungal infection that affects the superficial layers of a dog’s hair, skin and claws. It’s an illness that can be both frustrating and painful for your pet, but thankfully, it’s not life-threatening and can usually be treated effectively with the assistance of a vet.

Dogs suffering from ringworm have usually come into direct contact with fungal bacteria, often through another infected animal or human, but also potentially from touching a contaminated object.

The trademark symptoms often appear seven to 14 days later, although some dogs are asymptomatic after the infection — this can wreak havoc if they’re placed in a crowded environment with other animals, such as a boarding kennel.

What does ringworm look like on a dog? Well, there are a few giveaways that vets look for during examinations.

• Round or irregularly shaped red markings on your pet’s skin, often raised from the surface
• Red, irritated-looking skin
• Persistently itchy skin
• Hair loss
• Hair regrowing on these crusty patches
• Appearance of dandruff-like flakes on your dog’s coat
• Broken hairs on the coat
• Brittle or broken claws

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Dog Hotspot vs. Ringworm

Another skin condition commonly misidentified as ringworm is hotspots, AKA acute moist dermatitis. This is also another bacterial infection, although the itchiness causes dogs to scratch and bite at the site, causing further inflammation or infection.

When this occurs, parents will spot patches of red, irritated-looking skin, along with swelling, crusting and hair loss. It’s easy to see how this is sometimes confused with untreated ringworm in dogs.

If you spot any itchy red patches on your dog, it’s important to call a vet straight away, so they can differentiate between the conditions. Both are treatable, but require different approaches.

Hotspots can be alleviated through the use of topical treatments, medicated shampoos, antibiotics, steroids or even the use of an Elizabethan collar — known as the cone — to stop constant scratching.

There are three types of fungi that can cause the infection:

• Microsporum canis, which causes an estimated 70% of ringworm cases in dogs. This typically lives in dogs or cats already infected and feeds on the keratin of the outer layers of skin, hair, and nails.
• Microsporum gypseum, which is responsible for an estimated 20% of ringworm cases in dogs. This is usually found in soil and is most common in South America.
• Trichophyton mentagrophytes, which brings about the final 10% of infections. This is found in moist areas and it commonly affects humans, too — Athlete’s Foot sufferers, this is the bacteria responsible.

Transmission — how is ringworm spread?

These fungi can stay dormant for up to 18 months and your dog can come into contact with them through a variety of ways:

• Contact with an infected animal or human
• Contact with contaminated objects (brushes, combs, dog bowls, furniture or bedding)
• Spores in soil
• Infected fleas

Can humans get ringworm?

Bad news — if humans come into contact with the fungal bacteria that causes ringworm via their dog, they can contract the skin disorder. 

Often our immune systems will fight off the threat before it takes hold, but young children, the elderly and immuno-compromised are at increased risk of catching the disease.

Thankfully, it’s rarely serious and can usually be effectively treated with the application of topical creams, sprays or gels over the course of a couple of weeks.

Can dogs get ringworm from cats?

Yes — people may think that, because dogs and cats differ biologically, that your dog can’t get ringworm from your cat, but it can. Ringworm can be highly contagious, so cross-contamination can occur. If you live in a multi-pet household, you should be aware of the potential risk.

So you suspect your pet is suffering from ringworm and you take them to the vet — what can you expect to happen?

First, your vet will start with an examination and will want to hear about your dog’s recent behavior. If you have strong reason to believe your dog has ringworm, you should inform the vet straight away so they can take hygiene precautions to prevent possible spread.

• Lesion inspection — If there are the distinctive red marks on the skin, the vet should be able to confirm if your dog has ringworm fairly quickly.  However, it’s not a failsafe method, as similar scaly, crusty rings can be caused by other infections (such as hotspots, skin mites or allergies)
• Fluorescence — Your vet will collect hairs belonging to your dog to be placed under a special light called a Wood’s lamp. Ultraviolet light can reveal the presence of fungi excretion attached to the hair. This only works for one type of fungal bacteria (Microsporum canis), so an absence of evidence might not rule out a ringworm infection.
• Fungal culture— This is the most accurate method. Vets will take a small sample of your dog’s hair or skin cells and send them off to the lab for closer inspection. If infected, the fungal culture will usually show as positive within ten days, but the results can take up to a month to show if the spores grow slowly.

Your vet may also choose to look at your dog’s hair under a microscope or perform a skin biopsy, but these methods are performed less often  due to comparatively low accuracy rates.

Early identification is key as this can prevent further spread. Once a dog is diagnosed, all other dogs in the household should also be tested, even if they’re symptomless.

Once the vet gets in contact with you to tell you your dog is infected with ringworm, they will recommend a treatment plan to eradicate the bacteria. Here are the main approaches when it comes to dog ringworm treatment:

• Topical treatments — There are a variety of creams and ointments which parents can apply to the infected areas, typically once a day for up to six weeks. Alongside this, your vet might also prescribe a medicinal shampoo, which can be used twice a week. This is usually left on for five minutes before rinsing. Consider wearing gloves when touching infected dogs, but at a minimum, thoroughly wash your hands after any contact. You can read more about how to bathe a dog with ringworm here.
• Oral Medication — Topical treatments might also be used in conjunction with antifungal medicine or therapy, which is usually taken for at least six weeks at a time. During this period, vets might take hair or skin samples from your dog at two week intervals to check the course of action’s working.
• Environmental management — Parents will need to disinfect their homes and keep it clean to prevent further spread of ringworm to other dogs or humans. This means trying to contain the infected dog in a space without carpets, while also mopping and vacuuming this area at least once a day. Bleach and antibacterial cleaning products can be used. In addition, bedding should be washed, as should other items that have touched your dog, like collars or brushes.
• Quarantine — It might seem harsh, but it’s for their own — and everybody else in the house’s — good. Do not allow the infected dog to come into contact with other pets or humans. Parents need to keep this up even if their dog’s already on treatment, as it can take up to three weeks before they stop being contagious. 

You may also want to consider some natural ringworm remedies for your dog.

Will I need to clip my dog?

If there’s fungal bacteria living in your dog’s fur, surely the sensible thing would be to shave it all off?

Well, this is only advised if the infection is particularly severe. This is because any small nicks or cuts your dog gets during the haircut could allow the fungus to spread further into the skin.

If you’re advised to clip your dog’s coat, be sure to dispose of the contaminated hair responsibly.

This depends on the severity of the infection. Some cases may be cured within weeks, while others can take months to successfully treat.

At first, you might see patches of hair loss get larger, which is normal. This should start to grow back from around the two-week mark. If you don’t see improvement at this point, you should inform your vet.

Your vet should take fungal culture tests at two to three week intervals to see if the treatment plan is working — three negatives in a row and your dog will get the all-clear.

It’s crucial that you give your dog the full course of medication, even if symptoms begin to disappear. Stop too early and you might see a recurrence of ringworm, leading you back to square one.

And, because ringworm fungal spores can cling to items such as your dog’s food bowls, bedding and brush, you may need to dispose of them. You might need to deep clean furniture and carpets, too. 

The process to banish ringworm from your dog and home is certainly time-intensive and patience-testing, but with a little persistence, it can be done.

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