DS, 2.10, keeps complaining of an itchy head and is scratching it like mad. I have bit combed repeatedly and despite not finding anything have applied not shampoo anyway. I have also been extra conditioning his hair and combing and brushing it. His scalp doesn't seem red or sore and his hair doesn't feel particularly dry. This has been going on for about three weeks now. Any ideas what it could be/how to treat it?