Hello, My 18month Daughter Keeps Having Some Allergy And Can't

Hello, my 18month daughter keeps having some allergy and can't seem to identify the root cause,only last night I thought she could be reacting to milk as I feed her with formula and fresh milk....also her concentration levels are low as when you call her name she never responds, but will respond to music or the starting song of her favourite cartoon? Do you think she has hearing problems?please help im really worried