What should you know about feline ringworm?

Despite its name, ringworm is not caused by a worm. Dermatophyte fungi grow in the outer layer of skin, hair, and nails. A cat may carry or show the infection, and people can develop an itchy, expanding rash after touching the animal, bedding, grooming tools, or shed hairs. On human skin, the edge may look raised or scaly while the centre appears clearer. The appearance can overlap with eczema and other rashes, so a clinician may need to examine or test the affected area.

Avoid sharing towels, clothing, brushes, or bedding until the infection has been assessed. Wash hands after handling the cat and clean washable fabrics and frequently touched surfaces. Arrange veterinary care for the cat and medical advice for any person with a new rash; treating only one household member may allow reinfection. Depending on the location and extent, care may involve topical antifungal treatment or oral antifungal treatment. Do not apply a pet product to human skin unless a qualified clinician specifically advises it.

Seek prompt medical advice if the rash is spreading, involves the scalp or nails, becomes painful, produces pus, or affects a child or someone with reduced immunity. Urgent assessment is appropriate for facial swelling, eye involvement, fever, or rapidly worsening tenderness. A persistent scaly patch after contact with a cat deserves review even when itching is mild.

Ask whether the appearance needs a skin scraping or other test, which treatment suits its location, how long to continue treatment after improvement, and how to reduce spread between people and pets.