CATS · Condition guide
Ringworm in cats: real veterinary cases
Ringworm is the most common contagious skin infection in cats, especially kittens, long-haired breeds (Persians are over-represented), and cats from rescue or shelter backgrounds. Despite the name, it's not a worm — it's a superficial fungal infection, almost always Microsporum canis. Classic lesions are circular patches of hair loss with scaling and crust, but presentations vary enormously and a fair number of carrier cats look perfectly normal.
Diagnosis combines Wood's lamp (only ~50% of M. canis fluoresces apple-green), trichography (microscopic exam of plucked hairs), and fungal culture or PCR. Treatment is two-pronged: systemic oral itraconazole or terbinafine plus topical decontamination of cat and environment (lime sulfur dips are messy but effective). It's zoonotic — humans, especially children and the immunocompromised, can catch it.
What vets typically check for
- Wood's lamp exam — only ~50% of M. canis strains fluoresce, so a negative result doesn't rule out.
- Trichography (microscopic hair exam) — look for spores around hair shafts.
- Fungal culture (DTM) or PCR — gold standard for confirmation and species identification.
- Oral itraconazole or terbinafine — typically 6+ weeks until 2 consecutive negative cultures.
- Environmental decontamination: vacuuming, bleach (1:10), wash bedding hot.
Not a replacement for veterinary care. Use this to walk into the conversation prepared, not to self-diagnose.
Real cases from the veterinary literature
Peer-reviewed reports our semantic search surfaces for Ringworm in cats (dermatophytosis). Click into any case for the full abstract — or run a personalised search with your pet's exact details.
- Combination of Systemic and Topical Treatment for Feline Dermatophytosis: A Case Report
· 2020 · United States
Dermatophytoses or ringworm are the most common fungal infections in dogs and cats. This zoonotic disease is called dermatophytosis.
- The first report of terbinafine resistance Microsporum canis from a cat.
The Journal of veterinary medical science · 2018 · United States
A 2-year-old exotic shorthair cat was brought in because it had bald patches and some mild scaling on its body. Tests confirmed that it had a fungal infection called Microsporum canis (M. canis), which is a type of skin infection. The veterinarians used special tests to identify the fungus and check how resistant it was to antifungal medications. They found that the fungus was
- Successful resolution of dermatophyte mycetoma following terbinafine treatment in two cats.
Veterinary dermatology · 2008 · United Kingdom
Microsporum canis sensitive to itraconazole and terbinafine was isolated from two cats presented with generalized dermatophytosis and dermatophyte mycetoma. Itraconazole therapy was withdrawn through lack of efficacy in one cat (a Persian) and unacceptable adverse effects in the other (a Maine Coon). Both cats achieved clinical and mycological cure after 12-14 weeks therapy w
- Efficacy of oral terbinafine in feline dermatophytosis due to Microsporum canis.
Journal of feline medicine and surgery · 1999 · Italy
This study looked at the effectiveness of a medication called terbinafine for treating ringworm in cats, which is caused by a fungus known as Microsporum canis. Fifteen cats with this infection were given terbinafine by mouth once a day for two weeks. Out of the 12 cats that completed the study, 11 of them, or 92%, were completely cured of the infection. The researchers suggest
- A Mother and Daughter with Tinea Corporis Caused by Microsporum canis Apparently Transmitted from a Domestic Cat.
Medical mycology journal · 2024 · United States
The patient was a girl (case 1) and her mother (case 2). The family had purchased a domestic cat five months previously.
Frequently asked questions
- Can I catch ringworm from my cat?
- Yes — ringworm is zoonotic. Most healthy adults shake it off easily, but children, the elderly, and the immunocompromised are at higher risk. Treat the cat, wear gloves when handling, wash hands frequently, and see your GP if you develop ring-like lesions.
- How long does treatment take?
- Typically 6-12 weeks of oral antifungals, continued until you have two consecutive negative fungal cultures. Stopping too early is the most common reason for treatment failure and re-infection of the household.
- Will it go away on its own?
- In otherwise healthy adult cats with strong immunity, mild cases can self-resolve in 1-3 months — but during that time the cat sheds infectious spores everywhere and exposes the whole household. Treating actively is faster, safer, and reduces zoonotic risk.