I think maybe the Dermatology Community may be able to help. It doesn't sound allergy related to me, but I'm not a Doctor .. I'd try Dermatology.
Could be an allergy or sun related if you live in a warm place,do the patches itch? are they raised? Possibly something on his hands he is rubbing onto his Face, has he pale skin or Dark skin Really you need to ask the Doc and then see a Dermatologist if he says so.
Oh, don't worry I have the same thing on my cheek. It's just wring worm, it's a type of fungle infection. It's not harmful but it stays for a while if not treated.