What is Ringworm?

Ringworm, despite its name, is not caused by worms or bacteria. It is a contagious fungal infection that affects your dog's skin, hair, scalp or nails. The medical term for ringworm is dermatophytosis. The name "ringworm" comes from the characteristic red, raised, and often ring-shaped rash that can develop.

The fungi responsible for ringworm belong to the dermatophyte group, and they thrive on dead tissues, such as the outer layers of skin and nails. Ringworm on dogs may present itself as circular, red, and scaly lesions. Hair loss is also a common symptom, and the affected areas may appear crusty or inflamed. Dogs can contract ringworm through cross-species transmission, contaminated objects, or environments where the fungus is present. This is what ringworm on dogs looks like:

ringworm on dog nose dog licking ringworm spot
dog with healing ringworm on head Ringworm lesion on dog

Canine Species:


Microsporum canis:

This is the most common fungus that causes ringworm in dogs. It can also infect other animals and humans.


Microsporum gypseum:

This fungus is often found in soil and can infect both animals and humans.


Trichophyton mentagrophytes:

This type of ringworm can affect various animals, including dogs and cats, as well as humans.


Ringworm questions and answers. You may ask any unanswered questions on Discord.

Frequently Asked Qutestions

Common questions regarding Ringworm on Dogs.

2 questions

The medical term for ringworm is dermatophytosis. It is not caused by worms or bacteria, but by over 40 species of fungi. The name "ringworm" comes from the characteristic red, raised, and often ring-shaped rash that can develop.

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Highly! Ringworm is highly contagious and can spread through direct skin-to-skin contact with an infected person or other dog, or by touching contaminated surfaces. Ringworm is a zoonotic disease, meaning it can be transmitted from pets to humans, or from pets to animals and vice versa.

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Identification & Testing

How to identify and test your dog for ringworm.

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You can test for ringworm on your dog with the following methods:

Wood’s lamp examination:
Ringworm can glow with a yellow-green fluorescence under a ultraviolet light sometimes referred to as a Wood’s lamp.

Fungal culture:
Special hair and skin scraping kits can be purchased. Samples are taken from the affected area and sent to the lab for analysis. This method takes additional time becauase the sample needs to grow in a lab culture.

Microscopic examination:
This is usally done at the Veterinarian's Office. The doctor may take scrapings of the affected area and conduct an examination of the samples to confirm the presence of ringworm. This is usually faster but more expensive then sending a fungul culture by mail.

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There are four different stages of ringworm.

Stage One:
Infection occurs. During this stage, the infection is not visible to the naked eye. This is the incubation stage. It can take anywhere from one to three weeks for symptoms to appear.

Stage Two:
The dog will start developing small, raised bumps/lesions on the skin with mild redness and scaling. Treatment is advised to stop the spread.

Stage Three:
During this stage, the lesions on the skin become larger and more inflamed. The red patches of skin will look more like a ring at this point. You should seek treatment, or take your dog to the vet.

Stage Four:
This is the most severe stage. It includes hair loss, sores, scabs and severe itching. Ringworm has spread over most of the dog's body. Although, not life threatening, you should seek immediate treament or medical attention for your dog.

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