an anti fungi agent, available in cream/lotion.
No, steroid creams may make it look a little better for a day or two, but it will soon worsen. Ringworm is a fungus, and Cortizone 10 is basically an anti-inflammatory - it won't cure a fungal infection. Talk to your pharmacist about over the counter treatment for ringworm.
Take it to the Vet and have it wormed. There are OTC wormers, but you really have to be careful with dosing. <><><> Ringworm is a misleading name- it really has nothing to do with worms- it is a fungus infection of the skin- similar to athlete's foot. There are ointments that can be used to treat ringworm- problem is, dog's like to lick- and some of the human medications should not be used on a dog due to licking them. Check with your vet for recommendations. For humans, Lamasil or Chlotrimazole ointment works very quickly.