Ringworm In Dogs And Cats

What is ringworm?

Ringworm in dogs and cats is a skin disease that is caused by a fungus that affects pets and humans. Because the lesions are usually circular, and because in the past they thought it was caused by a worm, it is called ringworm.

So it is caused by a fungus! Ringworm in dogs and cats is zoonotic, meaning that is affects animals and humans, and it can be transmitted between them.



Ringworm looks like a round area of hair loss in dogs or cats that can be scaly and reddened or just roughened. The two most common types of ringworm in dogs and cats are Microsporum canis and Microsporum gypseum.

A good cleaning solution for material that may be infected with ringworm is a one in twenty solution of bleach and water.

How is ringworm diagnosed?

Ringworm can be diagnosed three ways:

1. Some cases of ringworm have a “typical” look to them so they are quite easy to diagnose.

2. A special ultraviolet light source (Wood’s lamp) is used. Hair that is positive for the fungus will glow apple green.

3. Some hair from the affected area can be placed on a gel (fungal culture) and monitored for fungal growth.

How did my pet get ringworm?

There are several sources that could infect your pet. And if your pet does become infected it could take 10-14 days to show clinical signs.

1. An animal or person that carries ringworm.

2. An animal or person that has clinical signs of ringworm.

3. Bedding, clippers, or other material that has come into contact with an infected animal.

Not all pets or people that are exposed will develop ringworm.

Ringworm treatments:

Most ringworm infections will heal in a couple of months with no treatment. But most veterinarians prefer to treat ringworm for faster resolution. The treatment they choose usually depends on the severity of the infection:

A: Keep all pets suspected of having ringworm away from other pets.

B: Grisiofulvin: this is an antifungal given orally and needs to be given from one to two months.

C: Topical antifungal cream: like ketaconazole cream, applied topically to the lesions.

D: Dips or antifungal shampoos.

E: Shaving the affected area to remove infected hair shafts.

Ringworm Vaccine:

A vaccine against ringworm is being marketed currently. This vaccine is designed to lessen, not necessarily prevent the infection of ringworm. You need to talk to your veterinarian about whether this vaccine is for your pet.

Go to: Free Ask a Vet.