Sinusitis

Infection
The “common cold” and other viral infections of nose cause the release of histamine release. Histamine has an effect on blood vessel dilatation, which can resulti in inflammation and swelling of nasal tissues. The inflamed nasal tissues are congested with blood and produce large amounts of mucus which increase the degree of nasal blockage. In the period of viral infection, the nasal immune resistance is decreased. This is why the chances of catching bacterial infections of the nose and sinuses are increased after a cold. When the nasal discharge turns to greenish or yellow, it means that you are encountering a bacterial infection.

Sinus infections
If your symptoms persist more than 1 week after a common cold, acute rhinosinusitis is likely to develop. Nasal congestion and thick mucopurulent discharge are increased. Headaches and sinus pain  may occur in the cheeks and upper teeth, around the eyes and at the forehead. Fever may also relapse. If your symptoms persist for more than 3 months, the sinus infection will develop to the chronic stage. Prominent symptoms are nasal obstruction and foul smelling nasal or postnasal discharge. The pain is not striking. You may suffer a dull headache or feel of not as fresh as usual.