What Causes Red Spots On Face,shoulders And Chest?

hi my baby at 1mth old developed red spots on his right cheek which then spread all over his face, scalp, shoulders and chest.2weeks later its turned into thick dry, flakey skin that he rubs on blankets and grabs with his hands. im applying aqeous cream and dont use any products on him.saw the GP when the rash had covered his face and she suggested baby acne.im concerned it may be exzema as i suffer from asthma, exzema and hay fever. also he has a runny nose and also passes very bad smelling wind very often which ive never known in such a young baby (now 10wks).he is exclusivley formula fed after unsuccessful breastfeeding, im concerned this could be an allergy???