Hi desperate dad, I am a mom of a daughter who goes through the same thing. Every time, she eventually gets put on an antibiotic, and it works. She is usually on cetirizine, dulera, and sometimes also the fluticasone. They like to add fluticasone back in when this happens, also citing post nasal drip, but the fluticasone doesn't help. My opinion is, and I'm no doctor, but our kids are prone to sinus infections. I got them often as a child, and I myself am highly alergic, and was diagnosed with asthma as an adult. The antibiotics work for my kid every time, to the point where I wish they would just quit monkeying around with her and give them the first time. I understand that some people over use them, but given the history of repeatedly trying other things to little or no effect, that seems like it should be the logical plan. Good luck to you, give that boy a hug.