Patch of fur missing.

My son's cat has a patch of fur missing from his leg. He is a black cat and all you see is the white skin in that area. No excessive grooming and no chance it was pulled out in a fight. He is an indoor cat and has a housemate. They get along very well. No signs of irritation at the site. Any thoughts as to what this might be? Alopecia does not seem a possibility. Thanks

Well, you can't watch your cat 24/7 so maybe you missed something? Keep an eye on the skin and if it looks bad , the patch gets larger, or if there's more of them you'll have to check with your vet. As vague as it is now it could be anything from a flea you somehow missed to food related.

Loss of hair could indicate ringworm. I hope it's not.