Many dogs and cats have skin problems during their lifetimes, especially when they are puppies, kittens, or in their senior years. Various stressors such as being in a shelter, travel, or illness can put a pet at a higher risk. There is one skin infection that is becoming increasingly common: Ringworm.
The name would imply that it caused by a worm. In fact, it is a fungal infection of the skin, hair, and nails. In humans it often has a characteristic round red raised border. Yikes! Did I say humans? Yes, ringworm may be spread between us and our furry pets.
Let’s learn more!
The ringworm fungi are called dermatophytes and the scientific name for ringworm is dermatophytosis. The spores of the dermatophyte fungi are very hardy, and can live in the environment for years. Spores can be found in soil or can be shed from infected animals. For a ringworm infection to be transmitted, the spores need to come in contact with the skin. Once the spores bind to the skin, the dermatophyte fungi grow and feed on the dead cells of skin, hair and nails. A spore has many similarities to a seed.
In dogs, ringworm may appear as dry, discolored, scaly patches of skin with hair loss that may or may not be circular. The lesions might be itchy or develop scabs and crusts. The ringworm fungi grow and release spores which can spread the infection to other pets or their owners. Some dogs are “carriers” and do not develop an active infection.
Did you know that some breeds are more prone to ringworm? Yorkshire, Jack Russell and Boston terriers are all at higher risk. Dogs that dig in the soil, as well as hunting dogs may be more likely to be exposed. Ringworm is more common in humid climates and in kennels or shelters with a high density of dogs or cats. Rescue dogs and cats transported from southern states to Vermont are especially vulnerable.
How is ringworm diagnosed?
Because ringworm can mimic other skin conditions, your veterinarian will need to review your pet’s history and carefully examine the skin lesions. If ringworm is suspected, the veterinarian may examine hair samples or skin scrapings under the microscope to look for fungal spores. In addition to microscopic examination, a special light (called Wood’s Lamp) with a magnifier may be used to confirm ringworm diagnosis. In a darkened room, the ringworm infection may appear green under this special wavelength light.
If microscopic examination or use of the Wood’s Lamp does not confirm a ringworm diagnosis but ringworm is suspected, the veterinarian may recommend a fungal culture, biopsy or more advanced PCR test.
How is ringworm treated?
First, your veterinarian may prescribe oral medication, topical medication or both.
Second, disinfection of the home environment is extremely important to prevent re-infection or spread to other pets or family members, especially young children.
- An infected pet may be confined to one room that can be easily cleaned. It is important to minimize exposure to other pets or people. The use of gloves when handling the pet will help to reduce exposure to others.
- All bedding or pet toys that cannot be easily cleaned should be discarded and all other bedding and toys washed. Any grooming tools must be disinfected.
- Cleaning all hard surfaces regularly, vacuuming carpet daily and cleaning with diluted bleach solution or all-purpose cleaner will remove and kill the spores.
The ringworm spore is hardy in the outside environment but is easily removed in the home environment by cleaning, washing and disinfecting.
The first line of defense against ringworm is knowledge and an understanding of how the disease is transmitted. If you or your pet develop a skin condition that you believe may be ringworm, it is important to seek medical care.
Written by Andi Levesque, LVVS Veterinary Assistant