Ringworm in Cats: Symptoms and Treatments

Ringworm is a type of fungal skin infection caused by mold-like fungi called dermatophytes. In cats, the most common dermatophyte species, responsible for almost all ringworm infections, is Microsporum canis.

These fungi feed on keratin, a fibrous protein found in the outer layers of the skin, hair, and nails. They produce a vast number of spores that are released into the air, coating toys, furniture, bedding, and floors.

Cats can pick up dermatophyte spores either by being near an infected animal or spending time in a place an infected animal has been. These fungal spores that lead to ringworm can remain dormant on different surfaces for up to 18 months.

If one of your cats has ringworm, it’s generally best to assume that any other cats in the house have also been exposed. However, contact with the fungus doesn’t always result in infection. Cats will often simply groom the spores from their coats or other bacteria competitors will outnumber and defeat them.

While the condition can affect all cats, individual susceptibility to ringworm depends on a few different factors. Ringworm is much more common in kittens, elderly cats, and long-haired breeds.

The reason for this is likely to do with grooming: younger and older cats might be less thorough in their cleaning habits, and longer hair stops spores from being removed, particularly in areas that have become matted or tangled.

The most common symptom of ringworm is patchy hair loss, which usually occurs in circles on the head, ears, and legs. It can also be found on their chest and along the ridge of their back. You might also see scaling or crusty skin, inflamed areas, and changes in skin and hair color. However, some cats may be completely asymptomatic. Ringworm lesions can also be similar in appearance to those of various other skin conditions.

A vet will confirm the presence of ringworm in one of two ways: using a special light or by examining hair samples. They may use a special ultraviolet light known as a Wood’s lamp. Most of the common species of fungi that cause ringworm glow with a yellow-green fluorescence when the skin and coat are examined.

However, the most accurate way of diagnosing ringworm is to send hair samples and skin scrapings off to a laboratory for specialist testing. This can take quite a lot of time — up to 4 weeks for a definite negative diagnosis.

Ringworm is a highly contagious condition, and infections can occur in domesticated animals and humans when exposed to the fungus spores.

Healthy adults are resistant to infection unless the spores come into contact with a cut, graze, or pre-existing skin condition. The elderly, young, and those with a weakened immune system though are much more susceptible to the condition.

If left alone, the cat’s immune system will fight off the infection in around 3 to 5 months. However, it’s better to get your cat treated by a vet because of how infectious the condition is.

The most common way to treat ringworm is through a combination of anti-fungal drugs administered orally and topical treatments. These may take the form of creams, ointments, and special formula shampoos. If the lesions are present on many areas of a cat’s skin, a full-body rinse or dip may be used.

Treatments generally last for a minimum of 6 weeks, and testing can be done periodically to see if the spores are still present. If 2 back-to-back tests are negative, then your vet will likely tell you to finish the treatments.

You should also let your vet know if you have other animals in the house. They will be able to provide you with the best advice for your specific circumstances. It may be the case that you need to treat them all.

While your cat is being treated, it is best to keep other pets away from them by confining them to a specific area of the house. Make sure also that you always wear gloves when you are handling them.

With aggressive treatment, the cat will only be contagious for around 3 weeks. However, if the treatments are not carefully followed for the duration of the course, this time increases dramatically.

The house should be thoroughly cleaned regularly to remove as many spores as possible and reduce the possibility of recontamination. Daily mopping of all rooms and areas accessible to your cat helps with this.

Clean with diluted bleach to kill fungal spores. Carefully follow the instructions on the label to get the right dilution. Generally, you want around a quarter of a cupful of bleach per gallon of water.