I had an outbreak 3 years ago. My vet prescribed Program, the same stuff used for fleas, at a high dose. Also he gave me something called Trezaderm to put on the spots. This combination worked very well. Program has the advantage according to vets of being less toxic than Trifulvin. You won't have any flea trouble while the cats are on it.

I took the hygiene precautions and kept it from spreading to the rest of the house.

Ringworm is a pain but requires patience to deal with.