What causes blockage of sinus drainage, leading to inflammation?
|Rakesh Chandra, MD
Clinical Practice Director
Northwestern University Feinberg School of Medicine
Department of Otolaryngology-Head & Neck Surgery
About the author: Dr. Rakesh Chandra is Clinical Practice Director and Associate Professor in the Department of Otolaryngology-Head and Neck Surgery at Northwestern University in Chicago, Illinois. He is an Editor in Chief for the American Journal of Rhinology and Allergy.
Is it viruses? Allergies? Is it from anatomical blockage? The answers are yes, yes, and yes. But for all of the above, the answer is also an emphatic maybe.
Certainly a few percent of patients who suffer from the common cold will go on to have chronic sinus inflammation and infection. In that situation, swelling from the viral upper respiratory infection never seems to go away and then lasts three months and beyond. We think inflammation from the cold causes bacteria to get trapped in the sinus, which in turn triggers even more inflammation. Patients experience any combinations of symptoms including nasal congestion or blockage, runny nose or post nasal drip, alterations or loss in sense of smell, and facial pressure. Strictly speaking, these symptoms must be supported by objective evidence of chronic sinusitis as assessed by the physician during physical exam, nasal endoscopy, or a radiographic study.
Allergies are a more complex issue, because they affect different people in different ways and at different times of the year. Although allergic inflammation can cause bacteria to collect in the sinuses, many patients with allergies and chronic sinusitis have no bacterial element that can be identified. Moreover, a lot – maybe one third – of people with a presumed allergic chronic sinusitis have no allergies at all when they are tested. Why?
Many of these patients have allergy that is local to the nose but is not apparent in other parts of the system. Also, sometimes the inflammation persists well after the allergen has left the environment. Additionally, there are lots of ways the immune system overreacts to things, causing swelling inflammation, but are not classic allergic reactions. This is a subject of significant research these days.
Finally, some patients do have anatomic problems resulting in a tendency for the sinuses to get blocked. This is usually because of the way the patient developed during childhood and puberty, but it occasionally found due to trauma to the nose or face. Still, in the vast majority of cases, a purely anatomical reason for why a patient gets chronic sinusitis is unusual. It is usually that the patient’s anatomy predisposes him or her to sinus inflammation as a result of the various other causes noted above. Surgery for chronic sinusitis is another topic altogether. For now, suffice it to say that surgery compensates for these inflammatory causes by making the anatomical passages wider.