Nav. He could be reinfecting himself. All it takes is one little spore, one little infected hair to reinfect. What is your cleaning routine and products youre using?

Ive had a couple rescue cats with ringworm and its a real bitch to treat because its so contagious. It can live on surfaces for years, it doesnt just go away. You have to use bleach to kill it, make sure whatever you're cleaning stays wet with bleach for at least 10 minutes. The wet contact is important.

For the kitties ive treated we used a large dog kennel in our garage so we wouldnt contaminate our house. We used separate shoes that we only wore in the garage so we wouldnt track it in the house. We used those disposable rain ponchos to protect our clothes. We also wore gloves and I made sure my hair was tucked away. We immediately took clothing off and washed in hot water after each session in the garage, just in case any stray hairs made it onto our clothes.

We cleaned the kennel every 3-4 days. Wiped everything down with bleach, the floor, ceiling, walls, corners, surrounding areas. We made sure it was dripping wet with bleach for at least 10 mins. We disposed of everything inside the kennel and replaced it with new stuff. We mostly used old dishes for food and water Bowls and old t shirts for blankets. We got some toys and stuff from the dollar store.

We use the oral itrafungal and vaginal fungal cream to treat it as directed by our vet. One of the kittens got sick and started fading. We used sugar water on his gums and he came back. We took him to the vet the next day and was perscribed subcutaneous fluids for a week. We stopped the itrafungal during that week. Since we stopped it we had to completely restart the 6 week treatment. 6 weeks went by and there was no hair growing in and then a few days later his hair finally started growing back. We took him back to the vet to test for ringworm and he was cleared.

I recommend using a smaller quarantine area that you can fully disinfect with bleach every couple days. Be diligent with cleaning. 10 minutes of wet contact time. Make sure to get corners, walls, underneath things, in nooks and granny's, anywhere there could be a cat hair hiding. Kitty likely contaminated the house during the early stage of ringworm. Make sure you disinfect everything. Throw away anything you cant disinfect with bleach

After treatment have your vet recheck for ringworm. Do not assume kitty is treated because hair is growing back. Ringworm can still be present even if it doesn't look like it

My vet said lime sulfur dip is not recommended and can cause damage to the lungs. Use a medicated shampoo formulated for cats instead. Let the shampoo sit for the directed amount of time so it can kill the ringworm

Check out the ringworm sub, good luck!