What is sinusitis? How can I understand that I have sinusitis?

Chronic rhinosinusitis means a condition that lasts for 12 weeks at least and has at least two of the following symptoms: 1. Nasal obstruction, 2. Nasal discharge or postnasal drip, 3. Face pain, pressure on the face or “fullness”, 4. Reduction in the smell sense. Acute rhinosinusitis is a transient infection of the sinuses, usually caused by a cold. Chronic rhinosinusitis is a more permanent problem that occurs following a cold and requires a specific treatment approach. Since the symptoms are at a lower grade, those can be ignored both by patients and doctors.