3 yo has lost weight

[SienaSun]

My 3yo is small - always been on 25th centile for weight and between 2nd and 9th for height.
I weighed him last week and realised he'd lost a bit of weight since he was last weighed about 6 months ago - only 1/2 kg but he's dropped from 25th to 9th centile.
I've taken him to GP who said monitor it and bring him back in a month to be reweighed.
He's pretty lively and has a good appetite and eats really well.
He has always sweated a lot in his sleep and in the last couple of days he's complaining about itchy feet and is scratching them in his sleep.
He's generally healthy but always seems to have a mild cold and cough, which I think is normal for young children.
Should I be worried and take him back sooner to the dr?

you are concerned, so it might be worth to make an app with the gp. mention what you say nere about sweats and itchyness.

apart from the good apetite, is he alert and bouncy (as a 3yo should basically never sit still), good pallour (sp?)/healthy looking face (no eye rings, puffy eyes), meeting age appropriate milestones?
he might just be slight.

He is super bouncy and yes he's meeting all his milestones. He seems really well.
I googled "3 year old weight loss, night sweats, itchy feet" and it came back with lots of pages about cancers so I am freaking out a bit.
But maybe he was a bit overweight before and is now a more healthy weight for his height. Not sure if I am being over anxious.

Sounds like you should try to get to the bottom of it - I don't see the point in waiting. He's lost weight when he should be gaining / staying on his centile... that's missing a milestone. Worth checking.

A month does seem a long time to wait....I'll take him back. Thanks for replies.