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seriously? dr. neil chadha

We ask the experts to settle common questions we've all wondered about.

QUESTION Is there any truth to notion that, if you have a cold, you should refrain from blowing your nose? Some people apparently believe that frequently blowing your nose will only worsen your cold symptoms.

ANSWER A cold is an infection of the nose and upper airways caused by a virus, the most common culprit being rhinovirus. The typical blocked nose, runny nose and sneezing are a result of inflammation in the lining of the nose and sinuses caused by a chemical release triggered by the cold virus.

Fortunately, most colds run a straightforward course, resolving after a few days. Occasionally, bacteria may thrive in the mucus environment caused by a cold virus, leading to a "secondary" bacterial infection. It has been suggested that nose-blowing might increase the likelihood of developing secondary bacterial sinusitis by forcing mucus into the sinuses (air-filled spaces in the bones of the face connected to the inside of the nose by narrow passages).

Researchers from the University of Virginia studied healthy volunteers to evaluate whether nose-blowing would cause a special dye - dripped into the back of their noses - to be forced into the sinuses. They also ran other tests to see what pressures were generated in the nose by blowing, coughing and sneezing.

Their study found that nose-blowing could generate very high pressures - much higher than coughing and sneezing. In all four subjects, fluid was indeed propelled into the sinuses.

The study had some flaws. For example, the nose-blowing tests were performed while the subjects lay on their backs, and the subjects did not actually have colds so the pressures generated by nose-blowing may not have reflected real life.

Nonetheless, the study was noteworthy as it suggested vigorous nose-blowing might possibly contribute to the development of sinusitis by providing a mechanism for mucus and bacteria to get into the sinuses.

We do not know whether the risk of forcing mucus into the sinuses may be reduced by blowing the nose gently, or by blowing only one nostril at a time (while using a finger to block the other side). However, these might seem like logical measures to take.

Nose-blowing into a handkerchief is now widely considered unhygienic, as the cloth can become a reservoir for virus particles. We can reduce the urge to blow our noses during a cold by using decongestants such as nose sprays, nose drops, or other decongestants taken by mouth, although decongestants should only be used for a few days and are unsafe for some people.

The best advice is probably to blow your nose gently if you need to, but if the nose feels so blocked that it would require very high-pressure blowing, to consider decongestants, or even simple steam inhalation (being careful not to get burned).

It is interesting that in some cultures, such as in Japan, nose-blowing is frowned upon, particularly in public places. Maybe they are onto something.


Dr. Neil K. Chadha is a Fellow in the Department of Paediatric Otolaryngology - Head and Neck Surgery at The Hospital for Sick Children in Toronto.

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