What Does Ringworm Look Like on a Dog and How Is It Treated?
What to look for and how to clear it up.
You spotted a bald, scaly, or slightly crusty patch on your dog and went straight to Google at 11pm. First: take a breath. What you’re looking at could be ringworm, and despite the name, there’s no worm involved. Ringworm is a fungal infection caused by a group of fungi called dermatophytes (skin-loving fungi that feed on keratin, the protein in hair and skin). It’s common, it’s treatable, and knowing what to look for makes all the difference.
Here’s what you need to know about dog ringworm symptoms, how it spreads, how vets diagnose it, and what treatment actually looks like so you can stop spiraling and start helping your dog.
TL;DR
- Ringworm in dogs is a fungal infection, not a parasite. It causes circular patches of hair loss, scaly or crusty skin, and sometimes itching.
- It’s contagious to other pets and to people, so the sooner you get a vet involved, the better for everyone in the household.
- Diagnosis usually involves a Wood’s lamp (an ultraviolet light exam) or a fungal culture (a lab test that grows the fungus to identify it). Treatment combines antifungal medication, medicated shampoo, and thorough cleaning of your home.
- Lemonade pet insurance can help usually cover diagnosis and treatment of ringworm
What does ringworm look like on a dog?
The classic image of ringworm is a neat, ring-shaped patch, but on dogs it’s often messier than that. Early stage ringworm on a dog typically shows up as a small, round area of hair loss with skin that looks flaky, red, or slightly crusty at the edges. The center of the patch may look relatively normal while the border is more inflamed, which is where the “ring” idea comes from.
You might notice ringworm on your dog’s belly, face, ears, paws, or along the back, though it can appear anywhere. In some dogs, especially those with longer coats, the hair loss is subtle at first and easier to miss. Here’s what to watch for:
- Circular or irregular patches of hair loss (skin lesions) that may grow over time
- Skin that looks scaly, flaky, or crusty around the edges of the bald patch
- Redness or mild inflammation in and around the affected area
- Brittle or broken hairs at the edge of the patch
- Occasional itching, though some dogs show no discomfort at all
- Thickened or discolored nails if the infection spreads there
Dog hotspot vs. ringworm: how to tell the difference
A hot spot is a moist, red, and often weepy patch of irritated skin, usually caused by bacteria triggered by scratching or allergies. Ringworm tends to be drier, with a more defined circular edge and clear hair loss at the site. Hot spots also tend to appear suddenly and grow fast, while ringworm spreads more gradually. That said, both need vet attention, and only a vet can confirm which one you’re dealing with.
How does a dog get ringworm?
Ringworm spreads through direct contact with an infected animal, person, or contaminated surface. The most common culprit in dogs is a fungus called Microsporum canis, the same species responsible for most cases in cats. Your dog can pick it up from another dog at the park, from a shared grooming tool, from contaminated bedding, or even from soil where the fungal spores can survive for months.
Puppies, senior dogs, and dogs with a compromised immune system are more vulnerable because their defenses aren’t as strong. A healthy adult dog may come into contact with dermatophytes and never develop an infection at all, while a younger or immunocompromised dog in the same situation might.
Can you get ringworm from a dog?
Yes, and this is important. Ringworm is zoonotic, meaning it can pass between animals and humans. If your dog has ringworm, anyone in your household can potentially catch it through contact with the dog or with surfaces the dog has touched. Children, elderly family members, and people with weakened immune systems are at higher risk.
In humans, ringworm typically shows up as a red, itchy, ring-shaped rash on the skin. If anyone in your home develops a suspicious rash while your dog is being treated, they should see a doctor. The good news: with prompt treatment for your dog and some basic hygiene precautions (washing hands after handling your dog, avoiding sharing bedding), transmission risk goes down significantly.
If you also have cats at home, ringworm in cats is equally common and cats can both catch it from your dog and pass it back. All pets in the household should be examined if one is diagnosed.
How vets diagnose ringworm in dogs
Your vet won’t just eyeball the patch and call it ringworm. There are a few ways they’ll confirm the diagnosis, and it’s worth knowing what to expect.
Wood’s lamp exam
A Wood’s lamp is an ultraviolet light that your vet shines on the affected area in a darkened room. Certain strains of Microsporum canis will glow a yellow-green color under this light. It’s a quick, non-invasive first step, but it’s not foolproof since not all ringworm strains fluoresce, so a negative result doesn’t rule ringworm out.
Fungal culture
A fungal culture is the most reliable way to confirm ringworm. Your vet will collect a few hairs or a small skin sample from the edge of the lesion and send it to a lab, or place it in a special growth medium in the clinic. The fungus is then grown and identified under a microscope. The catch: this process can take one to three weeks, so your vet may start treatment before the results come back if the clinical signs point clearly to ringworm.
Dog ringworm treatment: what to expect
Treating ringworm in dogs is a multi-pronged process. There’s no single pill that fixes everything overnight, and cutting corners usually means a longer recovery or a rebound infection. Most treatment plans run six to eight weeks, sometimes longer.
Topical antifungal treatment
Your vet will likely recommend a topical antifungal medication applied directly to the affected area, along with medicated shampoo baths two to three times per week. One common option is a lime sulfur dip, a solution applied to your dog’s entire coat to kill fungal spores on the skin and fur. Fair warning: it smells strongly of sulfur and can stain fabric and surfaces, so plan accordingly.
Oral antifungal medication
For more widespread or stubborn infections, your vet may prescribe oral antifungal medication, most commonly itraconazole or terbinafine, taken daily. These work from the inside out, targeting the fungus systemically throughout the body. Your vet will determine the right dog ringworm medicine and dose based on your dog’s size, age, and overall health.
Environmental decontamination
This step is easy to overlook and critical not to. Ringworm spores shed from your dog’s coat can survive in your home for a long time, sometimes up to 18 months, reinfecting your dog (or infecting you) long after treatment wraps up. Your vet will guide you, but in general this means vacuuming frequently, washing all bedding and soft toys in hot water, and disinfecting hard surfaces with a diluted bleach solution. Any grooming tools used on your dog should be disinfected or replaced.
Does pet insurance cover ringworm in dogs?
Vet visits, fungal cultures, weeks of oral antifungal medication, and medicated shampoos all add up faster than you’d expect. The good news: Lemonade pet insurance may be able to help cover diagnosis and treatment for ringworm, as long as your dog wasn’t already showing signs when you enrolled, and symptoms first appear after your 14-day illness waiting period.
Ringworm is also one of the few conditions that can lose its pre-existing status over time. Because it’s fully curable, if your dog has been completely symptom-free for 12 consecutive months, with no treatment, medication, or signs of infection, it’s no longer considered pre-existing. That means if ringworm came back after that 12-month window, it could be eligible for coverage.
Before we go
Ringworm looks alarming, but it’s one of the more manageable skin conditions your dog can get. Catch it early, get a proper diagnosis, follow through on the full treatment plan, and clean your home thoroughly. Most dogs recover completely within two to three months. The main things to remember: don’t skip the fungal culture, don’t stop treatment early even when the patch looks healed, and keep other pets and family members away from the affected area until your vet gives the all-clear. You’ve got this, and your dog will too.
Frequently Asked Questions
How contagious is ringworm from a dog to a human?
Quite contagious through direct contact with an infected dog or contaminated surfaces. People with weakened immune systems, children, and the elderly are at higher risk. Washing your hands after handling your dog and avoiding contact with the affected skin patches significantly reduces the chance of transmission.
What does early stage ringworm look like on a dog?
Early on, it usually looks like a small, round patch of hair loss with slightly flaky or crusty skin at the edges. The center may look relatively normal. It can be easy to miss under a thick coat, so check your dog regularly if you suspect exposure.
How long does dog ringworm treatment take?
Most treatment plans run six to eight weeks, sometimes longer depending on how widespread the infection is. It’s important to complete the full course of antifungal medication and medicated baths even after the patches appear healed, since stopping early is a common reason infections come back.
Can I use over-the-counter antifungal cream on my dog?
Always check with your vet before applying any human medication to your dog. Some over-the-counter antifungal products are not safe for dogs, and using the wrong treatment can delay proper care or cause additional irritation.
Does ringworm in dogs go away on its own?
In healthy adult dogs with strong immune systems, mild cases can sometimes resolve on their own over several months, but this isn’t reliable and risks spreading the infection to other pets and people in the household. Veterinary treatment is almost always the faster and safer route.
A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC. The statements do not apply to policies underwritten by other carriers.
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