For a child with 2 weeks of cold symptoms, how do you know when it's turned into sinusitis?

Clinical diagnosis: Acute sinusitis has nasality of speech, purulent nasal discharge, facial swelling and tenderness and sometimes warmth and redness over the maxillary sinus. There may be dental pain or swelling around the eye, and sometimes fever along with the sense of congestion. Any family physician will know how to diagnose and treat this effectively.

Very difficult: It is very difficult to say what is truly sinusitis, and what is a routine viral upper respiratory infection. All of us struggle with this diagnosis. It would be crazy to get ct scans on everyone with this. We usually rely on symptoms and physical findings. Fever, foul nasal discharge, headaches, etc lasting more than 2 weeks suggest sinusitis.