7 Symptoms of Allergies from Airborne Substances

What are airborne allergens?

The signs and symptoms are familiar to many:

Sneezing often accompanied by a runny or clogged nose
Coughing and postnasal drip
Itching eyes, nose, and throat
Allergic shiners (dark circles under the eyes caused by increased blood flow near the sinuses)
The "allergic salute" (in a child, persistent upward rubbing of the nose that causes a crease mark on the nose)
Watering eyes
Conjunctivitis (an inflammation of the membrane that lines the eyelids, causing red-rimmed, swollen eyes, and crusting of the eyelids).

In people who are not allergic, the mucus in the nasal passages simply moves foreign particles to the throat, where they are swallowed or coughed out. But something different happens to a person who is sensitive to airborne allergens.

As soon as the allergen lands on the mucous membranes lining the inside of the nose, a chain reaction occurs that leads the mast cells in these tissues to release histamine and other chemicals. These powerful chemicals cause the contraction of certain cells that line some small blood vessels in the nose. This allows fluids to escape, which causes the nasal passages to swell, resulting in nasal congestion.

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Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care August 1, 2017

Some of the above information has been provided with the kind permission of the National Institutes of Health (www.nih.gov).

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