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 contract 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.
Last Editorial Review: 3/4/2003
Some of the above information has been provided with the kind permission of the National Institutes of Health