Ringworm on Dogs

Ringworm on Dogs

Posted by Lianne McLeod D.V.M. on

Ringworm on Dogs

Ringworm, despite its name, has nothing to do with worms and is not actually a worm. Instead, it's a fungal infection that affects the skin, hair, and sometimes even dogs' nails. It's a condition that strikes fear into the hearts of many pet owners, but understanding it is the first step in dealing with it effectively.

Ringworm, scientifically known as dermatophytosis, is caused by various species of fungi, including Microsporum and Trichophyton. These fungi thrive in warm and humid environments, making your dog's skin a perfect breeding ground under the right conditions.

The name "ringworm" comes from the characteristic circular, red, and sometimes scaly lesions that often form on the skin. These lesions can vary in size and appear almost anywhere on your dog's body. While ringworm is more common in puppies and younger dogs, it can affect dogs of any age.

How it Differs from Other Skin Conditions

Ringworm in dogs can be mistaken for other skin conditions, such as bacterial infections or allergies. However, there are some key differences to look out for. Unlike allergies, which often result in itching and inflammation, ringworm in dogs typically causes hair loss, a circular pattern of lesions, and can sometimes be itchy.

To differentiate ringworm from bacterial infections, your veterinarian may perform diagnostic tests, such as a fungal culture or a Wood's lamp examination. These tests help confirm the presence of ringworm and distinguish it from other skin issues, ensuring your dog gets the right treatment.

image of ringworm spot

Causes of Ringworm in Dogs

Ringworm doesn't discriminate; dogs of all breeds and sizes can get ringworm. Ringworm is highly contagious and can spread when one dog comes in contact with an infected dog. A dog can also get ringworm from contaminated objects or environments, such as grooming tools, bedding, or communal pet spaces.

It's not just dogs that can transmit ringworm; humans can catch it too. This zoonotic potential underscores the importance of maintaining good hygiene practices when handling an infected dog.

While any dog can get a ringworm infection, certain factors can increase their susceptibility to this fungal infection. A dog with a compromised immune system, such as one with underlying health conditions or stress, is more at risk. Puppies and senior dogs are also more vulnerable.

Environmental factors, like living in a humid climate or sharing space with other infected animals, can elevate the risk. Additionally, dogs with skin abrasions or injuries are more likely to contract ringworm, as the fungus can more easily penetrate broken skin.

Understanding the causes and characteristics of ringworm infection is vital in ensuring the well-being of your beloved canine companion. In the next sections, we'll delve into the symptoms, diagnosis, and treatment options for this condition, so you can arm yourself with the knowledge to tackle ringworm infections head-on.

ringworm on a dog's paw

Signs and Symptoms of Ringworm in Dogs

Recognizing the symptoms and signs is paramount to swiftly addressing this fungal foe. Ringworm manifests itself in several ways, and the presentation can vary from dog to dog. However, there are some common signs to be on the lookout for:

  • Circular Lesions: These circular, red, and sometimes scaly lesions on the skin, are often accompanied by hair loss. They can appear on the head, ears, paws, or body.

  • Itchiness: While not always present, some dogs may experience itching and discomfort, leading to scratching and exacerbating the condition.

  • Crusty Patches: Raised, crusty patches on the skin.

  • Brittle or Broken Nails: In some cases, ringworms can affect the nails, causing them to become brittle or break easily.

  • Patchy Hair Loss: Areas of hair loss, which can appear like bald patches on your dog's coat. These are caused by weakening of the hair follicles by ringworm fungus.

  • Inflamed Skin: Redness and inflammation of the affected areas.

  • Spreading Ringworm: Over time, the lesions can expand in size, creating a larger circular pattern.

Remember that not all dogs with ringworms will display all of these symptoms. Some may have only one or two, making early detection all the more critical.

Additionally, It's important to note that ringworm can often be confused with other skin conditions, such as allergies or bacterial infections. Unlike allergies, which usually result in generalized itching and inflammation, ringworm tends to produce distinctive circular lesions. To confirm whether your dog has ringworm or another skin issue, a visit to the veterinarian is essential. 

ringworm dog

Diagnosis of ringworm Infection

Diagnosing ringworm infestations in dogs is a bit of a detective's job, requiring keen observation and specialized tools. When you suspect your dog may have ringworm, it's vital to consult a veterinarian to properly diagnose ringworm. The following diagnostic tools and techniques are commonly used:

  • Fungal Culture: A skin, hair sample, or nail sample is collected and cultured to see if the fungal species responsible for ringworm in dogs grows.

  • Microscopic Examination: Skin scrapings or hair samples are examined under a microscope to identify fungal spores.

  • Wood's Lamp Examination: A special ultraviolet lamp is used to check for fluorescence in the affected areas. The fungus microsporum canis causes a chemical reaction when it attaches to hair follicles, causing them to glow when a Wood's lamp shines. While not foolproof, this can provide an initial indication of ringworm spores.

  • Skin Biopsy: In severe or stubborn cases, a skin biopsy may be performed to confirm the diagnosis.

It's crucial to rely on a veterinarian's expertise for accurate diagnosis of ringworm infestations. Self-diagnosis or home remedies can often lead to delays in treatment and worsening of the condition.

cat and dog ringworm

Treatment of Dogs Ringworm

Once ringworm has been diagnosed, it's time to roll up our sleeves and start the battle against this fungal intruder. Treatment options abound, and your choice will depend on the severity of the infection and your veterinarian's recommendations. Let's look at some of the options for treating ringworm in dogs.

  1. Anti-fungal Medications: Oral medication, such as griseofulvin, itraconazole, or terbinafine, are often prescribed to combat the fungal infection from the inside out. An oral anti-fungal drug can take several weeks to show results, so patience is key.

  2. Topical Therapy: Antifungal creams or ointments can be applied directly to the skin. These topical treatment options can help soothe symptoms and prevent further spread of the fungus.

  3. Antifungal Shampoo: Medicated shampoo containing antifungal agents, like ketoconazole or chlorhexidine, can be used to bathe your dog and treat affected hair or skin.

  4. Environmental Cleaning: To prevent reinfection, thoroughly cleaning your dog's living environment is essential. This step includes washing bedding, grooming tools, and any surfaces your dog frequents with anti-fungal solutions.

Remember, to successfuly treat ringworm infections you must be consistent and adherence to your veterinarian's instructions. In more persistent cases of ringworm infections, additional treatment for ringworm may be necessary.

Recovery and Healing From the Fungal Infection

Recovery from ringworm is not a sprint; it's a marathon that can last up to 6 weeks. The exact timeline can vary, depending on several factors, including the severity of the infection, the treatment chosen, and your dog's overall health. Generally, you can expect the recovery process to unfold in stages.

Here’s how to monitor progress and know when your dog is ringworm-free:

  • Veterinary Guidance: Regular follow-up appointments are essential to evaluate the effectiveness of treatment. During these visits, your vet may perform fungal cultures or skin scrapings. Two consecutive negative fungal cultures will indicate successful treatment of your dog.

  • Visual Inspection: As a pet owner, you can also actively monitor your dog's progress. Continue to inspect your dog's skin for any signs of improvement or recurrence of ringworm lesions. Be vigilant for any new skin lesions or changes in existing ones.

  • Skin and Hair Regrowth: The return of hair on a previously infected animal is a positive sign. It indicates that the skin is healing, and the ringworm fungus is retreating. Keep an eye on the texture and thickness of the regrowing hair.

  • Behavioral Changes: It is important to keep an eye on your dog's behavior. If they become less agitated, stop excessive scratching, and seem more comfortable, these are encouraging signs that the healing process is underway.

  • Environmental Measures: Prevent ringworm infestations through environmental contamination by cleaning and disinfecting regularly. This step is crucial to prevent reinfection during the healing process.

Remember that ringworms can be persistent, and even when the visible signs have vanished, the fungus may still be present. Completing the full course of treatment and following your vet's advice is essential to ensure your dog is truly ringworm-free. With patience, diligence, and expert guidance, you can look forward to the day when your furry companion is back to their happy, healthy self.

ringworm tick


Preventing canine ringworm is a proactive approach that can save both you and your furry friend from the hassles of dealing with this stubborn fungal intruder. Let's delve into some effective preventive measures.

  • Regular Grooming: Consistent grooming not only keeps your dog looking dapper but also helps you spot any skin abnormalities early. Be vigilant for any signs of ringworm, such as circular lesions or hair loss.

  • Maintain a Clean Environment: Keep your dog's living space spick and span. Regularly clean and disinfect bedding, toys, and communal areas. This minimizes the risk of fungal spores lingering in the environment.

  • Isolation of Infected Dogs: If you suspect or confirm that your dog has ringworm, isolate them from other pets in your household to prevent the spread of the infection. Consult your veterinarian for guidance on how long isolation should continue.

  • Avoid Sharing Items: Don't let your dog share grooming tools, food bowls, or bedding with other dogs, especially if one of them has ringworm. Fungal spores can easily transfer from one item to another.

Ringworm and Humans

Ringworm, as the name suggests, seems like it should only affect our four-legged friends. However, it's not that exclusive. Here's what you need to know about the zoonotic potential of ringworm infestation and how to stay safe when handling infected pets.

Can humans get ringworms from dogs? Yes, humans can indeed get ringworms from dogs. Ringworm is zoonotic, meaning it can transfer between animals and people. The fungus responsible for ringworm can be transmitted through direct contact with an infected dog's skin, fur, or items they've come into contact with, such as grooming tools or bedding.

Young children, the elderly, and individuals with compromised immune systems are particularly susceptible to contracting ringworm from dogs through direct contact. Therefore, wear gloves and take precautions when dealing with an infected pet.

ringworm on human arm

Safety Measures When Handling a Dog with Ringworm

Here are some tips for keeping yourself safe;

  1. Wear Protective Clothing: When handling an infected dog, especially during treatments or cleaning routines, consider wearing long sleeves, pants, and gloves to minimize skin contact.

  2. Hand Hygiene: Wash your hands thoroughly with soap and warm water after any interaction with an infected dog or their belongings. This is a simple yet effective measure to prevent the spread of ringworm fungus.

  3. Limit Close Contact: While it's essential to provide care and comfort to your infected pet, minimize direct contact, especially with vulnerable individuals in your household.

  4. Consult a Physician if Symptoms Arise: If you develop any skin lesions or suspect you've been exposed to ringworm, consult a healthcare professional promptly for proper diagnosis and treatment.

Ringworm lesions in dogs should not cause undue panic, but it does warrant responsible handling and hygienic practices and controlling environmental contamination. With vigilance and care, both your canine companion and your household can remain safe and ringworm-free.

The Bottomline 

Ringworm in dogs may be a formidable fungal foe, but armed with knowledge and vigilance, we can effectively manage and prevent its presence in our beloved canine companions. Recognizing the symptoms, seeking a prompt veterinary diagnosis, and following a prescribed treatment plan are essential steps in ensuring our dogs' well-being.

Preventive measures, such as regular grooming, maintaining a clean environment, and isolating infected dogs, can significantly reduce the risk of ringworm. Moreover, understanding the zoonotic potential of ringworms reinforces the importance of proper hygiene when handling our four-legged friends.

Taking these proactive steps and adhering to safety protocols can keep our dogs and our families safe, ensuring a happy, healthy, and ringworm-free life together.


  1. Evason, M., Stull J. (September, 2016). Dermatophytosis (Ringworm) Information for Dog Owners. American Kennel Club- Canine Health Foundation. https://vet.osu.edu/sites/vet.osu.edu/files/documents/preventive-medicine/Dermatophytosis%20%28Ringworm%29%2020200123.pdf

  2. Moriello, K.A. (August, 2020). Dermatophytosis in Dogs and Cats (Ringworm). Merck Veterinary Manual.


  3. Centers for Disease Control and Prevention. (April 30, 2014). Ringworm. https://www.cdc.gov/healthypets/diseases/ringworm.html

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Lianne McLeod, DVM, is a former writer for The Spruce Pets, contributing articles for 11 years. Before Dr. McLeod began writing about pet care, she worked several years in small animal practice. She has written extensively about the care and keeping of exotic pets and pet health care. She now researches water quality and chronic disease at the University of Saskatchewan. Lianne McLeod earned her Doctorate of Veterinary Medicine from the Western College of Veterinary Medicine at the University of Saskatchewan. She also received a Bachelor of Science degree in biology from Simon Fraser University. She continued her education and received a Ph.D. in Epidemiology from the University of Saskatchewan. Now, she splits her time between her family, research and writing about pet health for all the animal lovers out there.

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