Penguin yes, seen the doctor frequently. He had a really bad year in year 4 where he ended up half time on the (not very many) days he actually managed in. Since then he's been sent for tests with paediatrician each winter round about February time as he's generally unwell through the winter.
Only thing they've come up with is dust mite allergy, which I think is not the cause.
It tends to only be end of the winter term, and most of this one he's ill. So his attendance is usually around 85% in the end.
Thing is though it's difficult to tell how bad he is. He gets panicky at the thought of being sick at school (won't go to the medical room unless sent, as opposed to dd2 who seems to live there) so as soon as he thinks he might be sick, he wants to have the day off. Once he's had a day off, he really doesn't want to go in the next day... that can last a very long time.
I think it's a mixture of anxiety, generally tendency to pick up any virus going, and not really liking school so any excuse to stay off is good.
It tends to be mild fever (around 37.7-38) headache, stomach ache and if his temperature comes up fast then he will vomit. He also usually has an ear infection or two which often starts it off. Obviously the temperature can't be faked (yes I do insist he takes it in front of me and not after having a hot drink!!) but I can't really tell with the other two how bad it is.
His hearing over the winter also will go down to (good year) around 30% with glue ear, can be as low as 10%.
But also when he's not so well, he's more inclined to lose concentration, and be then told off for misbehaving, and then he wants to go in less. It's a bit of a vicious cycle.