Ringworm in Cats

Ringworm is an infection of the skin, hair, and nails caused by fungi called dermatophytes, most often Microsporum canis. It is one of the most common infectious skin conditions in cats, especially in kittens, long-haired cats, and cats in crowded or shelter environments.

Look for circular or irregular patches of hair loss, often with flaky, scaly, or crusty skin and stubbly broken hairs. Lesions commonly appear on the face, ears, paws, and tail. Some cats are itchy; others show little irritation.

A subset of cats — "asymptomatic carriers" — spread spores without showing obvious signs, which is one reason ringworm can be hard to contain in multi-cat households.

Vets diagnose ringworm using a Wood's (UV) lamp (some strains glow), microscopic hair examination, and the gold-standard fungal culture or PCR test. Treatment usually combines:

• Topical antifungals — medicated shampoos, dips, or spot creams applied to the lesions.
• Oral antifungal medication — such as itraconazole — for several weeks.

It is essential to finish the full course of treatment and retest as your vet advises. Stopping early allows the infection to return.

Fungal spores are hardy and can linger in the environment for months. To contain them:

• Isolate the infected cat to one easily cleaned room.
• Treat all pets in the household as your vet directs.
• Wash bedding and grooming tools in hot water.
• Vacuum and disinfect surfaces frequently, discarding the vacuum bag or emptying the canister each time.
• Wear gloves when handling the infected cat and wash hands thoroughly afterward.

Yes — ringworm is zoonotic. In people it appears as itchy, red, ring-shaped patches on the skin. Children, older adults, and anyone who is immunocompromised are more susceptible. See a doctor if a person in the household develops a rash.