Ds is 2.5. Every few months he will have about 48 hours when he is 'unwell'. It's normally preceded by a grumpy day, then he has some rancid nappies and then develops a high temperature. He is a bit snuffly but no snot or sneezing.
Goes off his food and is very lethargic and clingy.
Then after a couple of days he is fine again.
It's so predictable that I'm wondering if it's some sort of virus in his system that shows itself every so often.
Did used to think it was teething related but he has all his teeth now.