Derm Spotlight: Feline Dermatophytosis (ringworm)
What is ringworm?
Ringworm is a common superficial infection that infects the skin, hairs, and nails. It is a fungal organism that binds to the hair follicle as a nutrient source and infects hairs. Transmission is by contact with an infected animal, the environment, or fomites (objects that carry infection like furniture and grooming tools). It is also zoonotic (infectious disease that can spread from animals to people).
What causes ringworm?
The name ringworm is a misnomer because it is not caused by a worm, but instead a fungus called dermatophyte. Although several species of dermatophyte can infect cats, the most common is Microsporum canis. Contact does not always lead to infection. Infection depends on many factors like an individual’s age, health, and immune system, to name a few.
What does ringworm look like?
Ringworm lesions are highly variable in cats. They can look like circular areas of hair loss with scaling. Some may have the classic ring lesion. Cats are typically not itchy unless there is an underlying allergy or secondary bacterial or yeast infection. Unfortunately, ringworm lesions are non-specific and can look like other skin diseases.
How is ringworm diagnosed?
The most sensitive and specific diagnostic tool is a dermatophyte culture, which allows for species identification. Other diagnostic tools include Wood’s Lamp to look for fluorescent hairs, trichogram (examining hairs with the microscope), PCR testing, and skin biopsy (histopathology).
How is ringworm treated?
Although ringworm is a self-limiting disease, once diagnosed, treatment is almost always necessary since it is highly contagious to other animals and people. Treatment can take several months. Since ringworm is quite hardy in the environment, decontamination is imperative to prevent re-infection.
- Moriello, K. A., Coyner, K., Paterson, S., & Mignon, B. (2017). Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Veterinary dermatology, 28(3), 266–e68. https://doi.org/10.1111/vde.12440
- Bajwa J. (2020). Feline dermatophytosis: Clinical features and diagnostic testing. The Canadian veterinary journal = La revue veterinaire canadienne, 61(11), 1217–1220.
If your cat has symptoms or a diagnosis of ringworm please call or contact us.