RINGWORM (DERMATOPHYTOSIS), A FUNGAL INFECTION, IS THE MOST COMMON CONTAGIOUS SKIN INFECTION IN CATS. It can also affect the nails. Ringworm can be transmitted from cats to other animals and to people.
NOT A WORM, A FUNGUS
Several different fungi can cause ringworm. Feline cases are usually caused by Microsporum canis, Microsporum gypseum, or Trichophyton species. The fungus is most commonly found on an infected animal or in the infected animal’s living quarters. Spores shed into the environment can live for up to 24 months. Spores can live on brushes, bedding, furniture – anything the infected animal has touched.
Most healthy adult cats are naturally resistant to ringworm. Kittens under a year old are most often infected. Sick cats, senior cats, and free-roaming cats seem to be at increased risk. Genetics may also play a role, as Persians appear to be more susceptible to ringworm.
Ringworm usually appears as small round, scaly, hairless lesions on the head, ears, or tail. The lesions may itch, grow, and develop pustules. Occasionally, the infection will affect the entire body. Excessive shedding and hairballs may also occur. Ringworm can also cause nails to grow malformed.
If you have cats in your home, be careful about bringing a new kitten into the mix. Also, exercise caution when visiting cat shows, kennels, and groomers. If you see any sign of ringworm, isolate the cat and seek prompt veterinary attention. Also, wear gloves when handling affected animals and wash hands well afterwards.
DIAGNOSIS AND TREATMENT
Ringworm is most reliably diagnosed with a routine fungal culture of the skin and coat. Your veterinarian will also look for underlying disease(s) that may increase ringworm risk.
An antifungal cream with miconazole or thiabendazole is typically the first line of defense against a single lesion of ringworm. More severe cases typically also require a combination of oral treatment with an antifungal drug plus lime sulfur dips. Treatment generally continues until two weekly fungal cultures return negative results.