What Is Ringworm?
Ringworm is a common name for a fungal infection of the skin. Microsporum Canis is the name of the chief fungus responsible for ringworm in cats.
The outer layer of the skin is made out of a protein called keratin. There are types of fungi – called dermatophytes – that feed off keratin and cause skin infections. Their spores – microscopic seed-like structures – can be found everywhere around us. Given the right conditions, these spores can germinate and cause a fungal infection of the skin such as ringworm. Jock Itch and Athletes’ Foot are fungal infections of the same type.
Cats can carry ringworm spores without developing an infection. This means the tiny spores may be on their hair, but they don’t germinate on the cat’s skin, never causing any visible symptoms. A cat gets an active infection when spores come in contact with the skin itself, find a break in its defense systems, germinate and begin to multiply.
Ringworm is infectious. It can move from cats to humans, and from humans to cats, and between cats (or humans!) Other pets can be infected as well. Kittens, elderly cats, or those with challenged immune systems are more susceptible to ringworm, although given high enough concentrations of spores, healthy adult cats can also develop the condition.
How Does Ringworm Infect Cats?
A cat can be a carrier of ringworm spores without actually developing an infection. There is a long way for spores to go from dropping on a cat’s coat, where it can be cultured, to actually invading its skin and forming an infection. The cat’s first line of defense is self-grooming. Licking the coat is likely to get rid of spores. Once ingested they no longer form a threat, as this type of fungus can only live on a mammal’s skin.
The spores that make it through the grooming session still need to get into contact with the cat’s actual skin. That’s why lesions often form on the more exposed areas of a cat’s body such as the ears and paws. However, even when the spores get to the skin, they still need to find a break in the skin itself in order to germinate. Even a tiny nearly-invisible break may be enough for them to take root, but without one, they will not be able to form a colony and create an infection. Last, but not least, spores need moisture in order to germinate.
Symptoms of Ringworm in Cats
Once a cat is actively infected it develops a lesion at the site of the infection. In mild cases, it can just look like redness of the skin, or even dandruff. In severe cases, it can spread all over the cat’s body causing scaly bald patches and itchiness. Typical infections are usually limited to small lesions, usually on the cat’s head, ears or legs.
Other skin conditions can cause similar symptoms, so only a vet can make the final diagnosis. The traditional test for ringworm is by culturing a sample of the lesion. This takes up to three weeks of incubation in the laboratory and sometimes yields false results, either positive or negative. A relatively new way to test for ringworm is called PCR testing. Samples are sent to a lab which maps out DNA chains and looks for the specific DNA of ringworm pathogens. Results come in much faster, usually within 1-3 days, and are more accurate. Sometimes additional culture tests may be needed in addition to PCR testing because non-viable spores can cause a false-positive result.
Treating Ringworm in Cats
Once the ringworm is confirmed, your vet will prescribe a course of treatment, which can include anti-fungal dips or shampoos and sometimes medication as well.
Work with your veterinarian on finding the best medications to use. Some anti-fungal drugs are very toxic and some are not very effective. Never use OTC drugs without first consulting your vet (that’s always true, for any drug and any medical condition). Be wary of recommendations for specific anti-fungal drugs that you read online. Griseofulvin, for example, is still prescribed by some veterinarians but it is outdated and dangerous and it has been superseded by more effective and less toxic drugs. Take some time to research this or ask around on our Cat Health forums, and discuss the choice of drug with your vet.
Lime-sulfur dips are not expensive and can be a very effective part of treatment. They are usually recommended once or twice a week – consult with your vet about the frequency. You may be able to find a pet groomer to do them for you, but this won’t be easy as many groomers refuse to treat animals with ringworm due to its contagious nature.
Clipping of the cat’s fur is sometimes suggested by vets. While it may be necessary in severe cases, clipping has its drawbacks. Clipping can cause microscopic cuts and bruises to the cat’s skin, where ringworm spores can take hold and form new colonies. It can also simply contaminate the treatment room with more spores.
Limiting the cat’s access to certain parts of the home can help with limiting ringworm contamination. It could be a useful step, especially with a highly infected cat and until you achieve some control over shedding using medication and lime-sulfur dips. Keep in mind that ringworm spores are airborne, so confining a cat to a crate won’t help. The spores will get out of the crate and into the room. Confinement of any kind can increase a cat’s level of stress, so use it cautiously and consider taking steps to lower the cat’s stress level.
If you’re dealing with a ringworm infestation in a multi-cat household, you will need to decontaminate the house. Cleaning is your first line of defense, as it helps mechanically move spores out of the house, as well as killing them with disinfectants. Reducing the number of spores to an absolute minimum prevents re-infection and future outbreaks. More on setting up the cleaning regime for a ringworm epidemic.
Dealing with a Ringworm Infestation
Ringworm can form a special challenge in multi-cat environments where it can transform from the odd lesion on a single cat into an infestation affecting multiple cats. In such cases, an overall environmental treatment is called for, and owners may find themselves faced with a long and arduous struggle against the invisible fungal spores.
Over the years, many of our members have faced such massive ringworm situations, and one of them, Bunnelina, wrote a great guide about dealing with ringworm. Some of the tips here were shared by her in this thread where you can read them in further detail and see how our member responded.
1. Educate yourself but don’t obsess.
Learn about ringworm (you’re doing that right now!) but don’t obsess. You’re all going to be fine!
Ringworm may be gross, but at least it is not deadly”, says Bunnelina. She suggests taking deep breaths and avoiding over-Googling “ringworm”, as you could soon get overwhelmed with information, along with misinformation and useless products for sale.
A good way to get support is by starting a thread in TheCatSite.com’s health forum. “I found help, encouragement, kindness, and commiseration here on TheCatSite! Discovering this community was the silver lining of my ringworm odyssey,” Bunnelina shared.
If you want to expand your knowledge about the scientific aspects of ringworm and its treatment, watch the video at the bottom of this article. It’s a webcast presented by veterinarian dermatologist Dr. Karen Moriello, DVM, where she thoroughly reviews ringworm, its symptoms, diagnosis and treatment. The webcast is directed at shelter workers and addresses issues that are more common in a multi-cat environment.
2. Get going
If you’re dealing with a ringworm infestation, time is of the essence. Reducing the number of ringworm spores on your cats and in your household can stop them from germinating and invading new spaces.
What to do if you don’t have a final diagnosis yet? Bunnelina suggests starting some treatments right away if your vet suspects ringworm. ” Don’t wait for the culture results,” she says in the thread.”Time’s a-wastin’ – don’t let the spores keep spreading for weeks”.
Your vet will probably not prescribe oral medications before the lab results on the culture are in. That’s because these medications are toxic and can have some nasty side effects. Unless there is actual ringworm to treat, medications may do more harm than good.
However, there can be a huge benefit to cleaning your home, and you can also consult your vet about starting lime-sulfur dips. This substance is harmless to cats and humans but kills ringworm spores, keeping them from spreading through your home. These dips aren’t much fun for the cat though, so do consult your vet and see if he or she thinks the situation warrants them. Your vet can also provide you with instructions about the right way to perform the dips.
3. Clean. A LOT.
Your goal is to reduce the amount of ringworm spores in the environment. The larger the number of spores, the more likely are a few of them to get past the body’s defense mechanisms and cause the disease. We found enough valuable information and housecleaning tips to justify a separate article: Housecleaning methods to get rid of a ringworm infestation. More on setting up the cleaning regime for a ringworm epidemic in this article.
4. Treat all animals at once
Concentrate your efforts and attack ringworm from every angle at once. Do everything at the same time, for both animals and humans who may be infected. This means oral medications as prescribed by your vet after the diagnosis, topical cream, and dips for everyone together.
At the same time, keep cleaning your house, so that you’re attacking the monster from every angle. Have your cats checked for fleas and mites as well, and treat accordingly, as these parasites cause microscopic skin injuries where ringworm can take hold.
Make sure the environment isn’t too damp, and keep things de-cluttered and clean.
Finally, here is the video webcast by Dr. Karen Moriello. It’s not short and a lot of it is intended for shelter workers, but if you have a ringworm infestation on your hands, it’s a great resource that’s well worth watching.
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