Congestion
When the lining of the sinuses becomes inflamed as part of a common cold, the natural self-cleaning process of our respiratory system stops functioning properly and causes more mucus to form. When the mucus is no longer moving properly, it leads to the common complaint of a blocked nose or congestion.
From a cold to sinusitis
When the mucus can no longer drain sufficiently, the narrow pathways between the main nasal passages and sinuses can become clogged which makes it easier for bacteria and viruses to grow and can lead to acute inflammation of the sinuses (sinusitis).