Sneezing

Sneezing, like coughing, protects the airways. It is an involuntary reflex action independent of a person’s will. Unlike coughing, the trigger for sneezing originates solely from the nasal mucosa, not the respiratory tract’s lining.

The stimulus travels from the nose via nerves to the medulla oblongata, which sends commands to engage various muscles typically involved in breathing and coughing.

Sneezing begins with a deep inhale. Breathing then stops completely, the soft palate rises to close the internal nasal passages, and exhalation muscles tense, increasing lung pressure. Suddenly, the soft palate lowers, opening the nasal passages, allowing a powerful, high-pressure air stream to pass through. This explosive airflow through the nasal passages removes foreign or harmful substances from the nose.

Sneezing can be triggered by many causes, the most common being a cold, also known as nasal catarrh, rhinitis, or the sniffles. Alongside headaches, slight swelling of the nasal mucosa occurs, making it hypersensitive to stimuli.

In such cases, sneezing can be provoked by stimuli that do not affect a healthy nasal mucosa, such as sudden temperature changes, strong airflow, touch, or smoke.

The characteristic “achoo” sound may signal a more serious infectious disease. Sneezing is almost always present in children at the onset of measles and is an early sign of influenza or other respiratory illnesses. Because seemingly harmless sneezing can herald a serious condition, the folk expression “bless you” or “to your health” is said to wish that it remains just sneezing.

A frequent cause of sneezing is hypersensitivity of the nasal mucosa (allergy) to substances like pollen, fragrances, dust, gases, or fumes, which provoke strong irritation. Certain substances, such as pepper, paprika, or tobacco powder, almost invariably cause sneezing upon contact with the nasal mucosa.

A weak sneezing stimulus can be intensified by looking at a bright light source, like the sun or a bulb. Sneezing can also be triggered by irritation of the external ear canal, such as earwax removal, or by nasal parasites.

Sneezing can be a hysterical phenomenon, more common in women, often following family or workplace conflicts or unfulfilled desires. Hysterical sneezing may persist for hours, weeks, or even months.

Sneezing can be deliberately induced by gases or powders known as sternutatories, which can cause intense sneezing episodes. Sternutatories, along with tear gases, belong to the group of irritant chemical weapons.