Despite its name, ringworm (also known as dermatophytosis) is caused by a fungus, not by worms.
Fungi, known as dermatophytes, can infect your dog’s hair and dead skin, leading to bald, scaly areas with broken hairs. These areas can show up simply as patches or as rings.
What does it look like
Ringworm shows up most often on the feet, face, ears, and tail.
The infection is usually confined to hair, nails, and dead skin. However, inflammation and redness of other parts of the skin can develop from the body’s immune response to the fungus.
This inflammation can cause your dog to itch and scratch, and secondary bacterial infection may develop. In addition, ringworm is infectious, and other animals or people in the household can contract it.
There are a variety of ways to diagnose ringworm infection.
Some of these fungal organisms will fluoresce under ultraviolet light. Therefore, your veterinarian may be able to diagnose ringworm during your dog’s visit by examining its hair and skin under a special light.
In some cases, your veterinarian may recommend a fungal culture. A sample of your dog’s hair and skin cells is placed on a special medium in an attempt to grow the fungus for both diagnosis and identification. Cultures can take several days to a couple of weeks.
Sometimes, fungal material can be visible directly under the microscope.
Ringworm can clear up on its own. But treatment speeds recovery and helps prevent infecting other animals (and people) in the household.
Repeated bathing with a medicated shampoo removes dead hair and skin and inhibits fungal development.
Oral medications are also available. In that case, treatment needs to continue for weeks to months. In addition, all pets in the household may need treatment because some animals can carry ringworm without showing any signs of infection.
You will need to clean or discard any bedding, brushes, and other household items in contact with your dog.
Ringworm in Dogs