My 3 Year Old Grand Son Seems To Scratching His

My 3 year Old Grand Son seems to scratching his Head a Lot....My Grand Daughter gives him a Bath every night...he also scratches behind his right ear....and on the arms at times...!!!!! Did not know if maybe he has Puritus = Itchy Skin ???? what are Your Recommendations as to what may be causing his Itching...there is NO cats or dogs etc..in the House and he is a Very happy Little BOY etc..with lots of Love from the sisters and whole Family etc..(:<)