Help with skin issues on feral cat

Hello this feral been coming around for a while he has it looks like Hair missing or scars on his legs and then some kind of like missing hair and scaly patches on his head. Also, his face also always looks scarred up. I don't know if he's been in fights, one night he showed up here he had blood all over his chest but the next day he had no cuts or anything, he seems very strong and healthy and I'm having a hard time getting good pictures because he runs off. I just wanna be cautious about anything like ringworm because I have leukemia and I'm immune compromised so that's some thing  My doctors told me to stay away from stray cats. All of the vets around here require appointments, and I never know when this cat is going to show up, any help would be appreciated. I'm posting the pictures I have