Battling ringworm with your kitten? It can seem scary, daunting, and sometime impossible to beat—but fostering kittens with ringworm saves lives.
Shelters typically don’t have the resources to handle ringworm, and these kittens are often put down. If you’re armed with knowledge (and a large glass of wine), you can help ringworm kittens get healthy and ready for their forever homes.
What is ringworm?
Ringworm (or dermatophytosis) is one of the most common skin conditions in kittens—and up to 20% of cats may be asymptomatic carriers, meaning they are carrying the organism (and can spread it to other cats) but aren’t showing outward symptoms.
Despite it’s name, ringworm has nothing to do with worms. It’s a fungal infection cased by three different types of fungi: Trichophyton, Microsporum, and Epidermophyton.
Ringworm gets its name due to the round, “ring-like” lesions that typically appear during infection. Cats may also show dandruff-like scaling, broken hair shafts, or areas of hair loss (often on the ears).
How is it spread?
Ringworm is a zoonotic disease—meaning it can be spread between animals and people. So if your kitten has ringworm, you’ll need to protect yourself during treatment. Studies have shown that in 30–60% of households with an infected cat, at least one person will develop ringworm. Children, elderly, and immunocompromised individuals are most susceptible.
It is highly contagious, especially in young kittens since their immune systems aren’t fully developed. When infected, microscopic spores are produced around infected hairs, which are the main source of infection for other kittens. The spores are naturally shed, so kittens can become infected by contact with a ringworm-positive kitten, or through their environment.
Ringworm is very durable in the environment and spores can live dormant for up to 18 months. Once in contact with the fungus, it takes 7–14 days for lesions to appear—though sometimes it can take up to 21 days.
How is ringworm diagnosed?
Visible signs—like circular areas of hair loss, broken hair shafts, and scaling or crusty skin—may indicate ringworm, but further tests are needed to confirm.
Wood’s lamp examination
A Wood’s lamp emits a particular wavelength of ultraviolet light that can cause ringworm spores to fluoresce an apple-green color. It’s estimated that 30–80% of M. canis strains will fluoresce. In my experience, the vast majority of kittens with ringworm have displayed a bright green color under a Wood’s lamp.
Medications (e.g. doxycycline, terramycin), detergents, and other environmental contaminants can also fluoresce, causing a false positive, which is why more testing is needed to diagnose ringworm.
A positive result strongly suggests ringworm, and the kitten should be isolated while further testing is done.
Direct microscopic examination (trichogram)
Direct microscopic examination is used to confirm the results of Wood’s lamp findings. Hairs and skin scrapings from the suspected infected areas are examined under a microscope. Infected hairs will appear swollen, frayed, or irregular.
A fungal culture is the best way to diagnose ringworm. A toothbrush can be combed all over the fur and skin, particularly focusing on the suspected lesions. Your vet will then send it to a lab to try and grow dermatophytes. The downside is that it can take up to three weeks to get fungal culture results.
Ringworm treatment: a 4 pronged approach
Pets typically recover from ringworm on their own in about three months, depending on their age and overall health. If you are in a single animal household with no young children or immunocompromised adults—and the infection is minimal—awaiting self-cure might be a good choice for you. Always consult your vet first.
In most situations, an aggressive, four pronged approach will be necessary to treat ringworm in kittens.
Oral medication is a crucial component to ringworm treatment, especially in a shelter or foster home.
There are several oral anti-fungal drugs available for kittens, but itraconazole, fluconazole, and terbinafine are the most commonly used to treat ringworm in cats. Compounded itraconazole is generally not recommended due to lower efficacy.
One of the most commonly used treatment protocols is itraconazole—one week on, one week off—for a total of five weeks. We’ve had great success with Intrafungol (an oral itraconazole medication) for speeding ringworm recovery.
These are all prescription medications which can be taxing on the liver, so it’s important to work closely with your veterinarian. Kittens on oral anti-fungal meds typically need to be weighed weekly to ensure proper dosing. Most are not safe for pregnant or lactating cats, or kittens under eight weeks of age.
Topical therapy can be helpful to minimize environmental contamination and help heal small, active lesions, but it is not effective as a sole treatment method. Creams and ointments—climbazole 0.5%, terbinafine 1%, thiabendazole in a commercial preparation, or any of the following at greater than 1%: clotrimazole, ketoconazole, or miconazole—can be placed on hard to treat areas, like the ears.
Tresaderm can also be helpful as a spot treatment for healing lesions, especially on the face.
Since cats can easily lick off topical treatments, they typically have limited efficacy and are not recommended as a sole treatment option.
- While the bottle suggests a 4% concentration, it’s safe to use an 8% concentration—especially for tough-to-treat cases.
- Use twice per week.
- Safe for pregnant animals, and those over three weeks of age.
- Try a spray bottle, rather than creating an actual dip. A spray bottle reduces product waste, lowers kitten stress, and decreases cross-contamination issues.
- Use cotton rounds soaked in the solution to treat the face, ears, and whiskers.
- Do not rinse or dry the kitten, but provide a heat source to keep warm while they dry naturally.
Anti-fungal shampoos, like Peroxiwash, are also an effective ringworm treatment. They tend to be more expensive, but way less smelly.
Environmental decontamination is crucial to ringworm recovery. Without decontaminating the environment, you risk reinfection.
Follow the five D’s of environmental decontamination: Diagnose, Discard, Debulk, Disinfect, Document Success.
Recognize, treat, and isolate infected kittens or carriers. Cleaning and disinfecting will not work if an kitten is continually reinfecting the environment.
Anything that can’t be easily washed—like scratchers—should be discarded. If it can be tossed in the washer, wash on the longest setting. I’ve had the best success using the “sanitary” setting on my washer, and tossing in a bit of color safe bleach.
Mechanical cleaning is the most important part of environmental decontamination. Clear surfaces and floor with something that will easily trap hair and dust, like a Swiffer. Carpets should be vacuumed thoroughly and treated with a commercial steam cleaner to destroy ringworm spores. While cleaning of the duct work isn’t typically necessary, filters and air vents should be cleaned or replaced.
Once all organic matter (dust, hair, etc.) is removed, treat with a disinfectant like Rescue at a 1:16 dilution, or bleach at a 1:32 dilution. Rescue is our disinfectant of choice due to its gentle, yet effective nature. Rescue can also be found in convenient wipes.
Success is documented through an environmental culture. Cut a Swiffer pad into small sections and wiped the possibly contaminated surfaces until the pad is dirty. Then complete a fungal culture. This can be done by a vet or at home.
Is there a vaccine?
A commercial vaccine (FeloVax MC-K) is available, but it is controversial and not commonly used. Kittens must be four months old before the initial vaccination can be given, and it requires two boosters for ringworm prevention or treatment. It only reduces signs of infection, but it does not eliminate organisms from the kitten.