Cat Ring Worm


Cat ring worm (ringworm) is actually not a worm, but a contagious fungal infection. The symptoms are easy to spot, but stubborn cases can be difficult to cure. Successful treatment often takes weeks or months before your cat is free of the disease.

Cat Ring Worm: What is it?

Cat ring worm is the most common infectious skin disease in felines.

Ring worm (known as dermatophytosis) is a fungus which lives on keratin (a protein found in skin, hair and nails). There are three species of ring worm that commonly infect felines.

The most of common of these is Microsporum canis. The other two are Trichophyton mentagrophytes (usually contracted through contact with rodents), and Microsporum gypseum/fulvum (usually contracted from contact with spores in the soil).

Generally, ring worm affects two different classes of cat; kittens, whose immune system has not fully developed, or adults who have been immunocompromised. A cat's immune system can often be weakened by stress, drugs, other diseases, or a disorder.

Cat Ring Worm: Transmission

Ring worm is spread by contact with fungal spores (called arthrospores). This can be through contact with an infected animal, or a carrier animal that shows no symptoms.

It also can be contracted through direct contact with the actual fungal spores in the environment (such as in soil). Like all spores, they are very resistant to environmental factors, and can live for up to 18 months.

Not all pets in a household or kennel that are exposed to ringworm develop the disease. Some may become infected but develop no obvious signs of the disease. Some of these animals will become carriers.

Contaminated grooming supplies and electric hair clippers can also transmit the disease.

In an infected animal, sheaths of arthrospores can be found around the infected areas (on hair strands, skin, or nails). These spores are shed, and then travel. They can commonly be found in carpeting, furniture, and cat bedding, as well as in air filters.

Ring worm is also the most common zoonotic disease, meaning that it can be passed from animals to humans. According to the Centers for Disease Control, cats, dogs, cows, goats, pigs, and horses can all pass ringworm to humans. It should be noted that M. canis can be transmitted to humans, but not all forms of ring worm can.

If your cat has ring worm you should take steps to prevent contracting it yourself. Use gloves and wear an apron when handling your cat, and wash your clothes right after contact with your cat.

Cats can also be asymptomatic carriers. If you have multiple pets, and one pet has ringworm but the others seem symptom free, it is possible that one of them is a carrier. You'll need your vet to help you sort that one out.

Cat Ring Worm Symptoms

The most common locations for infection are the face, ears, tail, and paws. Look for the following:

  • Loss of hair in circular patterns
  • Broken hair in circular patterns
  • Hair loss in irregular patterns
  • Scaly or bumpy skin
  • Red and inflamed skin
  • Itchiness (occasionally)
  • Deformed claws

Cat Ring Worm: Diagnosis

Obviously, a diagnosis of ring worm starts with noticing the visible signs and symptoms. If you suspect that your cat has ringworm take her to the vet immediately.

Your vet may use an ultraviolet lamp (Wood's Lamp) test, in which a bit of infected hairs/skin/nails is placed under the lamp. Areas infected with M. canis will 'glow' (only M. canis glows under the lamp).

Microscopic examination of hair and skin is also used for confirmation, but this depends upon the technical skill of the examiner.

The most reliable test for ring worm is to take a skin scraping and perform a fungal culture on it. This is usually done by sending the sample to a diagnostic labratory, but some vets will grow cultures in house.

Cat Ring Worm: Treatment

Ring worm is often what's known as a self-limiting disease. In other words, in many cases it will clear up on its own, but this can take several months. Not all cats are able to fight off the disease, and there is a possibility that genetic predisposition may be involved.

Some sources say that all animals, unless they are immunosuppressed, will eventually become immune to ring worm.

Medication can be given to assist in the healing process, and help stop the spread of the fungus. Those medications can be in the form of oral or topical antifungal treatments, medicated dips, sprays and shampoos.

Oral medications have been found to work best at treating and stopping the spread of ring worm in cats. There can be side effects from these, so you'll have to work closely with your veterinarian on this.

You may have heard about a vaccine for cat ring worm. It does exist, but it only treats the clinical signs of the disease, not the actual fungal infection!

Following an episode of ring worm in your cat, you'll want to ensure that your cat is fungus free. Have your cat retested by your vet.

It is recommended that all infected cats, especially long haired cats, be clipped. This allows topical agents to work better, and also prevents broken hairs from spreading the spores, causing reinfection.

Part of the treatment plan is to prevent reinfection, or infection of other pets and family members. In order to do this, you'll have to try to get rid of the spores.

This includes vacuuming at least weekly (preferably daily). If you have a bag vacuum, dispose of the bag each time you use it. It also includes treating all surfaces possible with a cleaning agent. The recommendation is to use a bleach and water solution in a 1 to 10 ratio. For fabric and surfaces that won't stand 1 to 10, a 1 to 30 solution can be used with repeated cleanings.

Obviously, be careful with this and don't let your cat, children, or other pets get into the wet bleach!

Suggested Reading: Cat Ring Worm

Ring Worm Symptom List

Cat Ringworm

For some pictures of what the symptoms of ring worm look like, take a look at the Feline Advisory Board Website

Ringworm and Cats



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