Ringworm

Ringworm is a fungal infection that affects the skin, and like any other fungal infection, it is very treatable.

Sources:

There are several places your cat could have acquired the ringworm from.  Some of the most common are listed here.

• Dirt.  Ringworm is endemic in the soil.  That means it is always present in the ground.  If your cat goes outside and likes to roll around in the dirt, then that could be one way they got it.
• Grooming equipment.  If your cat goes to a groomer, if another cat that had ringworm was combed or trimmed and the groomer was not aware of it, and those items used were not adequately cleaned and sanitized in between, then your cat may have gotten them from a comb or clippers used on them.
• Another animal or people.  Since ringworm is a fungal infection on the skin, it is not species specific.  So, if another animal in the house has it, or if you work in the dirt or have a child who likes to play in the dirt, one of you may have gotten it, and given it to your cat.  It is possible to spread ringworm without actually getting it.

Contagion:

Ringworm does not infect every mammal that touches it, because the immune system has safeguards in place for that.  A healthy developed immune system is resistant to ringworm, and this applies to most mammals.  There are some exceptions.

• Illness.  If your cat is sick or stressed when exposed to ringworm, then they are more susceptible.
• Trauma.  If your cat develops a scratch on their skin, which is then exposed to ringworm, such as getting contaminated dirt in a nail, and then scratching themselves, this can predispose to ringworm.
• Underdeveloped immune systems.  This is why kittens are so much more prone to developing ringworm.  Their immune systems are not fully developed, and so it is harder for them to resist it.
• Persians and Himalayans.  For unknown reasons, possibly a defective gene, these two breeds are much more susceptible to ringworm, and have a harder time eliminating it.

Treatment:

Treatment may not be simple, but it is effective, it may just take a while depending on why your cat developed ringworm in the first place, and how strong their immune system is.  Most cats will clear ringworm between 3 weeks and 3 months.  The following treatments are most commonly used alone, but can be used in conjunction under veterinary supervision.

• Topical.  For cats who have only a few small areas of ringworm that are not around the eyes or mouth, we will treat topically.  This consists of anti-fungal creams that are also used for athlete's foot.   The two most effective are miconazole and chlortrimazole, but anything labeled for treatment of ringworm will work.
• Oral.  Oral anti-fungal treatments are effective but can have potential side effects, and can be fairly costly.  We will use these most commonly for cats that have multiple areas of ringworm, or that have ringworm around the eyes or mouth.
  • Griseofulvin is the most commonly used ringworm treatment in cats.  It is the safest, and can be given for long periods of time if needed.
  • Itraconazole is effective against ringworm, but it can potentially have some fairly negative side effects.  We will only use this if griseofulvin is not an option.
• Dips.  Lyme dips are effective against ringworm, but they are not very pleasant for your cat.  They consist of dipping your cat in a foul smelling liquid, then letting them drip dry.  These are done once a week for several weeks.
• Shampoos.  There are shampoos designed to kill ringworm on your cat, and they do work.  The catch is that your cat needs to be bathed twice weekly and the shampoo needs to sit on your cat for a full 10 minutes before being rinsed off. 
• Other treatments:
  • Revolution, which is a topical flea treatment, has been shown to have slight anti-ringworm effects, so you can apply this to your cat to help increase the efficacy of other ringworm treatments.
  • Growing up.  Some kittens will clear ringworm on their own as they age and their immune system develops.  That can be a long time for you and your cat to live with ringworm though.

Elimination from the Environment:

Ringworm can persist in the environment for up to two years.  But, that doesn't mean your cat will keep getting it back.  We do recommend washing your cat's bedding in hot water, and cleaning all surfaces that you cat spends a lot of time on with a bleach based cleaner.

If you have any questions regarding any of the above, please feel free to contact us at All Feline Hospital at info@allfelinehospital.com.

This handout was written by Dr. Shelley Knudsen, DVM

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