Looking for advice on my white cat

Hiya looking for some advice/help. I have a pure white domestic cat, who doesn't go out. Male, 3 years old. Recently he formed a scab like thing on his head which is now healing but has developed one on his neck. Any ideas as to Wat it may be. He's scratching himself to bits with it.
Thanks xx

It could be a flea allergy, food allergy, or litter allergy.  I'd get him to the vet first to rule out anything medically wrong and get something to treat fleas and help stop the itching.  Then look at the other issues.

Definitely isn't fleas, he's had same food for about 2 years and litter always the same also. I'm going to take him to vets but was just querying to see for ideas X

They can develop an allergy to something they've eaten or used for a long time, so the fact that he's had the same food & litter for 2 years does not rule out an allergy. It could also be an allergy or sensitivity to something else, like the detergent or fabric softener you use on blankets he might sleep on.

Okay thank you