Ringworm Fungus in Bulldogs and French Bulldogs

By: Dr. Roy Kraemer |
DVM, Bulldog Specialist Veterinarian

Contrary to what some bulldog owners think, ringworms are not worms. The term dates back to when the cause was poorly understood, and the circular worm-like red-rash appearance led people to believe that a real worm was under the skin mistakenly.

Some pets are silent carriers and do not exhibit clinical signs yet they can infect other pets and human house members who are in contact with them and their surroundings

Fortunately ringworm is not common to bulldogs and Fr. bulldogs

bulldog ringworm fungal infection


Ringworm is a skin infection caused by a group of fungi known as dermatophytes. These fungi feed on keratin, a protein found in the skin, hair, and nails, which explains why the infection most commonly affects these areas.

Common Bulldog Ringworms

  • Microsporum canis: This is the most common dermatophyte found in dogs. It can also infect cats and humans.
  • Microsporum gypseum: While this fungus is more typically associated with cats, it can also affect dogs and humans. It is often found in soil, making it a less common, but still possible, source of infection for pets and people who come into contact with contaminated ground.

ringworm infection in Fr. bulldog

Bulldog and Fr. Bulldog Ringworm Transmission:

  • Transmission: Ringworm can spread through direct contact with an infected animal or person or with objects or surfaces contaminated with the fungus, such as bedding, grooming tools, or furniture.
  • Survival: The spores of ringworm fungi are notably durable and can survive in the environment under harsh conditions for extended periods. This resilience contributes to the spread and difficulty in eradicating the fungus.

Bulldog to Owner Ringworm ZOONOSIS

Pet owners can contract ringworms from their pets. Ringworm can be transmitted from animals to humans through direct contact with an infected animal’s skin or fur. The ringworm spores can also attach to pet bedding, grooming tools, furniture, and other surfaces. When humans touch these contaminated surfaces and their skin, particularly if there is a break in the skin, they can become infected.

Certain groups of individuals have less robust immune systems, making them more vulnerable to contracting ringworm:

  • Infants and Young Children: Young children, especially infants, have immune systems that are still developing.
  • Elderly Individuals: As people age, their immune systems naturally weaken.
  • People with Autoimmune Diseases: Autoimmune conditions can compromise the immune system’s effectiveness.
  • Immunosuppressed Individuals: People who are undergoing treatments that suppress the immune system, such as chemotherapy for cancer, are at increased risk.

Ringworm in Bulldogs and Fr. Bulldog PRE-DISPOSITION:

  • Compromised Skin Barrier: Although healthy pets and people with intact skin are generally resistant to ringworm, the fungus can enter through breaks in the skin, such as cuts, scratches, or other forms of damage. This makes the skin more susceptible to infection.
  • Immune-Suppressed bulldogs: Individuals with weakened immune systems
    • Puppies: bulldog puppies have undeveloped immune system
    • Senior: aging bulldogs might have a less robust immune system
  • Skin injury: bulldog with concurrent skin disease or skin trauma
  • Immune suppressing drugs: such as cancer patients and bulldogs on immune suppressant drugs like prednisone
  • Immune-suppressing diseases: like Cushing’s and hypothyroid
  • Stressed pets: anxiety, trips, kenneling, and noise, all of which impact the immune system
  • Pet crowded areas:  shelters and kennels

Ringworm in Bulldogs and French Bulldogs PRESENTATION:

Ringworm can often present with symptoms similar to those of other skin conditions.

Common findings are

  1. hair loss
  2. itching
  3. flaking

Only in certain cases, ringworm may manifest as its classic symptom: a raised, circular ring-shaped lesion on the skin.

Ringworm in Bulldogs and French Bulldogs / DIAGNOSIS:

Ringworm can closely resemble other types of dermatitis in bulldogs, but it’s relatively rare. Therefore, it’s important to consider and rule out more prevalent skin conditions such as allergies (flea, atopic, food), mite infestations (Demodex, mange), and infections (yeast, bacteria).

  1. Exam: Look for a ring-shaped patch of skin where hair is missing and the patch appears to expand outwards.
  2. Woods Lamp: Your veterinarian may use a Woods lamp, a type of ultraviolet light, to help identify ringworm infections. This test can make ringworm-infected areas fluoresce. It’s a preliminary tool and not definitive. The skin is often erroneously fluorescent when shined over topical medication and flakes.
  3. Fungal Culture: This is the definitive test for diagnosing ringworm but can take up to three weeks to yield final results.
  4. Microscopic Hair Exam: Hair samples can be examined under a microscope to detect the presence of ringworm spores or hyphae.
  5. PCR Test: PCR testing involves amplifying and analyzing DNA to detect the presence of specific pathogens, such as the fungus responsible for ringworm. This test provides highly accurate results and can help confirm the diagnosis of ringworms more quickly than traditional fungal cultures.

lldog ringworm woods light test

Ringworm Skin Fungus in Bulldogs / PREVENTION:


Maintain a relaxed environment to help bolster your bulldog’s immune system.


Ensure your bulldog receives a nutritious, well-balanced diet to support overall health.


Avoid the unnecessary use of drugs like steroids that suppress the immune system, as this can make your pet more susceptible to infections like ringworm.


A sound, healthy immune system helps protect your bulldog from infectious disease

  • Bully Immune Support
  • Bully Multivitamin Antioxidant Formula
  • Bully Fish Oil EFA


By managing itching and allergies effectively, you can maintain a healthy and intact skin barrier, which is crucial for preventing ringworm infections

  • Bully Itch & Allergy Chews
  • Bully Skin & Coat Derma Care
  • Medicated shampoos and conditioners

Additionally, promptly treat any skin diseases or cuts to prevent ringworm infection, and isolate infected household pets until their ringworm has been successfully treated and a follow-up culture confirms it is negative.

This helps prevent the spread of the infection to other pets and humans in the home.

Yeast Bully No Rinse Gel Handout - French Bulldog

Ringworm Skin Fungus in Bulldogs / TREATMENT:

  1. Environment: Ringworm fungal spores are resilient and can survive for a long time in your environment. Cleaning with diluted bleach is an effective way to eliminate these spores.
  2. Prescription Drugs: Treatment may require systemic antifungal medications such as ketoconazole, griseofulvin, itraconazole, and terbinafine. Most antifungal medications have potential side effects and typically necessitate preliminary screening tests and ongoing monitoring.
  3. Topical Treatments: In addition to systemic treatments, topical antifungal therapies can be applied directly to the affected areas. These might include:
    1. medicated shampoos
    2. creams
    3. ointments.


While the systemic drugs help kill the fungus, they do little to kill the ringworm spore.

Topical bully antifungals will kill the sports and prevent the spread the infection

Topical bully therapeutics are an affordable and safe option that effectively contributes to ringworm treatment without associated side effects. These topical solutions should be included as part of your comprehensive approach to managing ringworm, helping to target the infection directly at the site and supporting overall skin health.

  • Yeasty Bully Antiseptic Shampoo: combines both antibacterial and antifungal properties. It should be left on the skin for 10 minutes before rinsing
  • Yeasty Bully Antiseptic Gel:  like the shampoo, it is antibacterial and antifungal but does not require water. It can be left on the skin and coat like a mousse. It can replace the shampoo or supplement it on non-bath days
  • Yeasty Bully Spray: same mix as the shampoo and gel
  • Bully Conditioner: ItchLess, Hypoallergenic, or Soothing Aloe Oatmeal cream rinse conditioners are recommended as a follow-up to the shampoo

Yeast and Ringworm Bully Ultimate Therapeutic Bundle


Comprehensive Approach: Treating ringworm can be challenging and costly, particularly in households with multiple pets. It’s crucial to treat both the infected dog and the environment to effectively manage the spread and ensure a faster resolution of the infection. While many pets may naturally overcome an infection over several months, active treatment can significantly speed up recovery and minimize environmental contamination.

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The information provided on this platform is for general informational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your veterinarian regarding any medical condition. It's important to always consider professional medical advice promptly and not to delay seeking it based on information you've read on this platform. Any reliance on the information provided here is entirely at your discretion.

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