Crusty Balding Spot

I recently took in a feral kitten, and he has developed a spot on his head that is progressively losing fur. I have a vet appointment next week, but wanted opinions while we are waiting for the appointment.

The area has a bit of crustiness/redness, and almost looks to be raised. He does scratch at his face some. I haven’t seen any fleas or signs of ear mites, but that doesn’t mean he doesn’t have them, and the scratching makes me suspicious. I was also concerned about the possibility of ringworm. The spot showed up after we had already had him for nine days. Any thoughts?