How to Deal With Ringworm in Cats

What It Is & Causes

Ringworm is a fairly common but treatable infection that affects a cat's hair and the top layer of the skin. It's also one of the rare afflictions that can be transmitted to humans and it's fairly common for both pet owners and cats to deal with ringworm at the same time which is why pet insurance is helpful.

Despite its name, ringworm -- also known as dermatophytosis -- is not a worm or parasite; it's an easily-transmitted infection caused by a fungus called Microsporum canis when its spores come into contact with skin. The infection will show up as a ring-shaped, itchy rash. (There are two other less common species of fungus called icrosporum gypseum and Trichophyton spp that can also cause ringworm.)

These ringworm spores can survive in most environments but prefer warm and moist areas. They can be carried on dust particles or through the air. They originate in the soil but can eventually make it to a host's body where they survive by digesting keratin on the hair shaft, skin, and sometimes nails and reproducing, eventually causing the infection. Skin scales and hair are eventually shed along with spores, which can live for years and continue spreading to other animals.

Coming into contact with the fungus (directly or indirectly) doesn't necessarily mean your cat will develop ringworm: in some cases, they may be brushed off while your cat is grooming, simply become dormant, or even live on the skin without causing any negative reactions.

Ringworm is a zoonotic disease, meaning it can jump from animals (like cats and dogs) to humans and infect you as well. However, you (and your cat) will have to come into contact with a certain number of spores before you are infected. Contamination doesn't always equal infection, and infected cats are sometimes asymptomatic.

Most people are resistant to ringworm infections unless they have an open wound, scratch, or weaker immune system. (If you end up with symptoms similar to ringworm, visit your doctor to find treatment.) Most cases of ringworm in humans can be easily cleared up with antifungal creams and sprays.

Chances of being infected also depend on other factors such as age (especially kittens and geriatric cats who may have trouble grooming), any illnesses (such as feline immunodeficiency virus, or FIV), genetics, medications that may suppress the immune system, overall health, strength of the immune system, and additional factors such as overcrowding and stress. For example, animal shelters and catteries have a higher chance of having ringworm due to the number of cats sharing a small space.

Additionally, cats with longer fur -- such as Himalayans and Persians -- tend to have more trouble removing ringworm spores while grooming.

Symptoms

Common signs of ringworm include many of the following:

• Circular areas of hair loss
• Broken hair
• Scaly skin
• Inflamed skin
• Differences in fur or skin color
• Dandruff
• Infected nail beds or claws -- sometimes this is the only sign of infection
• Itching, sometimes to a point where the cat may injure themselves; occasionally, cats itching their ears and only their ears may be a sign of ringworm
• Excessive grooming
• Blackheads in younger cats
• Hyperpigmentation (darkening of skin)

These lesions look like red rings and often show up on a cat's head, front paws, or ears (although they can show up on the rest of the body in particularly severe cases). Humans who contract ringworm also have a similar red ring show up on the affected area.

Diagnosis

If you suspect your cat has ringworm, you should take them to the veterinarian as soon as possible to diagnose it. Ringworm looks similar to other conditions (such as fleas and mange), due to symptoms such as hair loss and itching.

Diagnosis may be done using several methods:

• Veterinarians may use a fungal culture on hair that is taken from affected areas and placed on a fungal culture medium, most commonly a dermatophyte test medium, which has a color indicator that turns red when ringworm begins to grow. However, this test can take a few weeks to grow.
• They may also use a fluorescent light known as a Wood's lamp to screen for ringworm by finding infected hairs since half of Microsporum canis spores have a yellow-green glow under the lamp (due to a metabolite that is secreted onto the hairs by growing fungi). Early on or during an active infection, the whole hair shaft glows, but as the infection clears and your cat heals, the area and number of glowing hairs will decrease.  These hairs will need to be examined further to verify ringworm, since fibers, dead skin cells, and other materials may glow. If your cat does test positive, Wood's lamp can be used to monitor treatment progress.
• Vets may also use a microscope to look for fungal spores by placing a clear tape on the lesion and staining the cells with a specific purple stain, which allows the ringworm spores to be visible (although it may still be difficult to see).
• A biopsy is an accurate way to diagnose ringworm; however, it's incredibly invasive and requires cutting out a piece of skin from your cat to send to a lab for analysis. This method can also take a few days to get results.
• A newer method that is used to detect ringworm is through a process called a polymer chain reaction (PCR) test, a non-invasive test that uses skin and hair to detect ringworm (although this will take a few days).

Treatment

Treatment for ringworm can take a few weeks or months, depending on the severity of the case. Typically, this includes an antifungal cream, spray, or lotion that is applied topically, such as miconazole and/or chlorhexidine. Since this can be groomed off easily by your cat, your vet may prescribe other treatments in conjunction with topical agents.

There are also oral antifungal medications (such as itraconazole, griseofulvin, terbinafine, and ketoconazole) prescribed for more serious infections that may not be cleared up with topical creams. (Kittens under 8 weeks will not be able to safely ingest these drugs, so you and your veterinarian will have to use a different treatment.) If your cat has an aversion to oral medications, you can get pills with a flavor they enjoy.

Veterinarians may clip your cat's coat -- either some or all of it, depending on the severity of the case and the length of their coat (it may be harder to spot ringworm on longer-haired cats) -- to get rid of the infection since ringworm can cause hairs to become fragile and shed spores into your cat's coat and the surrounding area, making it easier for ringworm to spread. Clipping the hair can reduce this spread.

You can also do a thorough full-body rinse or dip with a special shampoo (such as Malaseb shampoo) twice a week.

In some cases, a healthy cat may be able to fight off the infection on its own. However, you should still take your cat to the vet to make sure they get treated promptly.

Symptoms of ringworm typically improve after 2 to 4 weeks of treatment, at which point they should be reexamined with a Wood's lamp and fungal culture to see how well the treatment is progressing. Even after a negative fungal culture, you should still continue to monitor your cat and take them to the vet to get them checked.

Part of your treatment plan should also include cleaning the contaminated areas in your household to protect yourself, your cat, and any other pets in your home. (If you have other pets in your home, take them to the vet just to make sure they haven't contracted ringworm. You may also want to take precautions such as giving them a full-body rinse or dip.)

You'll need to keep your cat in an easy to clean area (preferably without carpeting) and clean surfaces and floors on a daily basis -- along with your cat's bed, blankets, and washable toys -- until the infection is totally cleared. Hot water and a bleach solution (1 part bleach & 9 parts water) work best to get rid of ringworm. Anything that can't be cleaned regularly should be discarded.

If you're using a vacuum cleaner or a mop, make sure that you'll be able to clean the attachments properly or simply dispose of the cloth after you are done.

You'll also have to clean areas around your home, such as furniture, drapes, and floors.

If you have multiple cats who aren't quarantined to a single room, it's a good idea to clean all your ducts and vent plates, since spores can travel through circulated air.

A dehumidifier can help you deal with the spores, since spores can live more easily in humid environments.

Be sure to wash your hands thoroughly after playing with your pet and if you have contracted ringworm yourself, make sure that you've cleared up the infection before you touch your cat again.

Not only can this help your cat heal from ringworm, but it can prevent spreading and getting infected again.

Prevention

Preventing a ringworm infection is difficult but possible. The most important factor is to keep your cat as healthy as possible since a healthy coat and skin is more resistant to infection. Make sure your cat is receiving the necessary nutrition, exercise, and care in order to thrive.

If you bring a new cat into your home -- especially one who hasn't been checked by a veterinarian yet or may be sickly -- you may want to quarantine them for a short time to prevent the potential spread of ringworm. 

How do I know if my cat has ringworm?

Symptoms of ringworm in cats include ring-shaped lesions on your cat, dandruff in your cat's fur, and scaly texture in the skin with red and circular patterns of hair loss.

How do I treat ringworm on my cat?

Treatment for ringworm typically includes topical antifungal medication to affected areas, oral medication, and (if your cat has a bad case of ringworm) a full-body wash or dip.

Can humans get ringworm from cats?

Yes. Ringworm is contagious and can be spread to people by contact with cats. However, it's fairly easy to treat.