Ringworm isn't a worm, but a highly contagious fungal infection. Untreated in a cat, it will run its course in about five months. However, letting it go puts other pets, and you, at risk for infection. Your cat will need veterinary attention, but fortunately you can treat her in the comfort of home.
Check Other Animals
Your infected cat might not be the only animal in need of ringworm treatment. If there are other pets in the house, consult your vet to determine if they're also infected, as some animals don't show outward symptoms of infection. Your cat may need to be quarantined from the rest of the family, or everyone may need treatment, depending on what the vet recommends. Regardless of who's getting treatment, it's wise -- and easier on you -- to limit your cat to a single room that's easy to clean, such as a room with tile floors.
In some cases, the first step to treating ringworm is clipping the infected cat's coat. Shaving your cat minimizes the amount of ringworm spores released into the environment and improves the penetration of antifungal shampoos. According to Dr. Arnold Plotnick of Manhattan Cat Specialists, a cat living in a home with elderly people, children or anyone with a depressed immune system should have her entire coat clipped. If the cat has five or more distinct ringworm spots or long hair, shave all her fur. Otherwise, a short-haired cat with fewer than five ringworm spots gets by with clipping the hair surrounding the spots. Take it slow when clipping your cat so you don't irritate her skin -- you don't want to release more spores and spread the infection. Use scissors instead of clippers around the infected areas to minimize dander, hair and spores flying into the air. Wash your grooming tools in a solution of one part chlorine bleach to 10 parts water to prevent the tools from spreading the fungus to your other pets.
Bathing is Key
Cats aren't known for their affinity for water, and being fastidious groomers, they usually aren't keen on salves and lotions on their skin. However, topical medication is an important part of ringworm treatment. Shampoos and ointments help remove spores, scales and crusts from your cat's coat and hasten the treatment process. The vet may prescribe a cream or ointment, such as miconazole lotion, usually used with a medicated shampoo. Some shampoos containing chlorhexidine don't require a veterinary prescription, while other effective options containing an antifungal such as ketoconazole are available with a prescription. Ask your vet to recommend a shampoo based on your cat's condition. Bathe your cat twice a week, keeping the shampoo in contact with her hair -- or skin if she's been clipped -- for 10 minutes. Be sure to sterilize the container you washed her in, such as the bathroom sink, cleaning it out with a bleach dilution after each use.
Time for Medicine
Your vet will likely prescribe a daily dose of oral medication, such as itraconazole, griseofulvin or ketaconazole, to complete your cat's treatment program. Each has potential side effects, including lethargy, vomiting and loss of appetite. Itraconazole is used more than griseofulvin, which has additional possible side effects, including nausea, anemia and jaundice. The vet will determine the appropriate drug and dose based on your cat's situation. Treatment time depends on the severity of the infection and how effectively the spread of spores is minimized; it may take as little as four weeks or as long as several months, until your cat has two consecutive negative fungus cultures.
Preventing More Outbreaks
Your home treatment for your cat's ringworm won't be limited to her -- you'll have to thoroughly clean house. Discard all items that can't be easily disinfected, such as cloth toys, collars and blankets. Cleaning blankets and curtains keeps spores at bay in your living spaces. Weekly chores include thorough vacuuming, dusting with electrostatic cloths and cleaning non-porous surfaces with a bleach solution. Whenever you handle your cat, wear gloves and a disposable smock or shirt, and wash your hands afterward.