Dude Key the Cat

Ringworm in Cats: Fungal Infections Among Felines

Cat Feline Ringworm Dermatophytosis

Ringworm is very rare, and more commonly found in homes with many cats under considerable environmental stress. Chain-smoking breeders can turn out a ringworm infested cat, too.


Ringworm is a fungus not actually a worm. The fungus can infect cats, dogs, and HUMANS. Treatment can be frustrating due to the often slow disappearance of the ringworm lesions and clinical signs. If you (or a pet) have ever had Ringworm, you know what I mean.


1.Topical therapy:

This consists of creams, dips or sprays applied directly to the affected area. Treatment should be continued for one week after signs disappear.

2.Oral therapy

With widespread distribution of spots, or in a case of ringworm that is nonresponsive to topical medication, oral medication is often prescribed. IT IS VERY IMPORTANT TO GIVE THIS MEDICATION EVERY DAY AND WITH A HIGH FAT MEAL (such as tuna in oil).

3. Adjunctive therapy

A. Medium to longhaired animals should be clipped for more effective treatment.

B. A vaccine was once available that was supposed to actually hasten the clearance of the clinical signs. Marketed by Fort Dodge® Labs, it is touted as a complete ‘cure’ for Ringworm, but the results were exceptionally poor. Like a few of the vaccines available today, to be sold, they have only to prove a disease exists, the vaccine exerts ANY control and is not dangerous to the pet. That is all. I do not rely upon it as a cure.

C.Vacuum carpeting and furniture at least once weekly. The infected hairs that are shed can remain infective for ONE YEAR!

D. Cats can carry the ringworm fungus but not show signs of the disease. All cats in the household should be tested with a fungal culture. If positive, these cats should be treated along with the primary pet.

If I suspect your pet has Ringworm, I will properly prepare an area on the cat’s coat with isopropyl alcohol, and then pluck some hairs and place them in a special media for growth of the offending organism. Very often, highly contagious fungi will change the media color within 72 hours. Less infective fungi will take up to a week. All this information helps me to give you a prognosis as far as recovery rates, and success of treatment.

My preference in the treatment of Ringworm is the use of the reasonably inexpensive Griseofulvin®, given daily. There are newer designer drugs which are much more exciting to talk about, but they can be associated with more internal organ damage and are no more effective than the old tried-and-true. Griseofulvin must always be given with food. The veterinarian will need to be sure of the type of Griseofulvin needed.

Remember: Ringworm is contagious to you! If your pet has lesions like Ringworm, have it checked out, pronto!

Dr Erik Johnson is a Marietta, Georgia Veterinarian with a practice in small animal medicine. He graduated from University of Georgia with his Doctorate in 1991. Dr Johnson is the author of several texts on Koi and Pond Fish Health and Disease as well as numerous articles on dog and cat health topics.