Thanks for checking in BB

Seems alright... but I can't confirm it 100% yet.
He's still sick after a full run of abx and we started a new one today. Although he does seem to be doing fine from a digestive standpoint, he's been doing quite bad for the past few weeks- we're now back to multiple NW's. I'm hoping it's 'just' a sinus infection.
On another note, I've noted that he's having red ears a lot in the evening and a google search has told me that it's potentially allergies. I'm a bit stumped and don't want to go there really. We had 2 days with no red ears this week after I've tried removing nutrios (cereals with no sugar added, but that contains corn and oats). We'll see.
What age do the allergy tests start being more reliable?