DS has had an itchy head for about a week, I have checked it several times (he has nice short hair thankfully - unlike DD!) and there is absolutely no evidence of nits. There is no redness (other than just at the bottom of his hairline where he has clearly scratched a bit), and nothing that looks like dandruff, flaky skin, eczema, psoriasis and so on - a normal pale scalp from everything I can see. It is not in one specific spot, he is complaining of it being mostly down the back, round the sides and behind the ears (which is when the nits alarms rang - but I really can see nothing and it has been a full week).
Should I treat him tonight anyway, as a precaution, even if we can't see anything?
Anything else it might be? Will be encouraging really thorough hair washing and rinsing in case it's shampoo residue or something but not sure that would cause him to scratch.
TIA for any tips.