Causes of Sinusitis

What are some causes of Acute Sinusitis?

Most cases of acute sinusitis start with a common cold, which is caused by a virus. These viral colds do not cause symptoms of sinusitis, but they do inflame the sinuses. Most people confuse a common cold with a sinus infection. Both the cold and the sinus inflammation usually go away without treatment in 10 to 14 days. The ensuing nasal inflammation might predispose you to develop acute sinusitis. The body reacts to a cold by producing extra mucus and sending immune cells to the lining of the nose, which, in turn congest and swell the nasal passages.

When this swelling involves the adjacent mucous membranes of your sinuses, air and mucus are trapped behind the narrowed openings of the sinuses. When your sinus openings become too narrow, mucus drainage is impaired This increase in mucus sets up prime conditions for bacteria to multiply.

Most healthy people harbor bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, in their upper respiratory tracts with no problems until the body’s defenses are weakened or drainage from the sinuses is blocked by a cold or secondary to allergic rhinitis (nasal allergies). Thus, bacteria that may have been living harmlessly in your nose or throat can multiply and invade your sinuses, causing an acute sinus infection.

Sometimes, fungal infections can cause acute sinusitis. Although fungi are abundant in the environment, they usually are harmless to healthy people. Fungi, such as Aspergillus, can cause serious illness in people whose immune systems are not functioning properly. Some people with fungal sinusitis have an allergic-type reaction to the fungi. This process is now called AFS (allergic fungal sinusitis).

As stated, chronic inflammation of the sinuses and nasal passages which is often seen in people with allergic rhinitis (both indoor and outdoor), can play a significant role in the development of acute sinusitis and chronic rhinosinusitis. Non-allergic rhinitis or vasomotor rhinitis, aggravated by humidity, cold air, alcohol, perfumes, and other environmental conditions, also may be complicated by sinus infections.

Acute sinusitis is much more common in some people than in the general population. For example, sinusitis occurs more often in people who have reduced immune function (such as those with immune deficiency diseases or HIV infection); with abnormality of mucus secretion or mucus movement (such as those with cystic fibrosis) and those with nasal septum deviation (crooked “divider” of the nose).

What causes chronic sinusitis?

There isn’t one cause of chronic sinusitis, per se, but inflammation is thought to play an integral part in the development of chronic sinusitis. For example, people who suffer from asthma (inflammation of the airways) are much more likely to have frequent episodes of chronic sinusitis. This has lead some researchers to investigate the link between asthma and chronic rhinosinusitis and referring to it as “one airway hypothesis”.

If you are allergic to airborne allergens, such as dust, mold, and pollen, which trigger allergic rhinitis, you may develop chronic sinusitis also. In addition, people who are allergic to fungi can develop a condition called “allergic fungal sinusitis.”
Also, if you suffer from chronic sinusitis, you may also be affected by weather changes (e.g. damp weather) or air pollution, much more so than the general population.

Like acute sinusitis, you might develop chronic sinusitis if you have an immune deficiency disease or an abnormality in the way mucus moves through and from your respiratory system (e.g., immune deficiency, HIV infection, and cystic fibrosis). In addition, if you have asthma, nasal polyps (small growths in the nose), or a severe asthmatic response to aspirin and aspirin-like medicines such as ibuprofen, you may experience repeat bouts of chronic, recurrent sinusitis.