Pollen 'Explosion' Has U.S. Sneezing
FAQ on Pollen and Allergy: Some Surprising Answers
WebMD News Archive
Is the 2010 spring pollen season the worst ever for allergy sufferers? continued...
As of mid-April, Kress says, SDI calculates that about 24.7 million
Americans have been affected by pollen and, to a much smaller extent, mold.
Last year at this time, the number was a bit higher: about 24.8 million spring
"Pollen counts are useless. What does a count of 2,000 really mean? So we
say look at the number of people affected," Kress says. "And in certain parts
of the country, like the Northeast, where it seems everyone says they're dying
from the pollen, the rest of the country is about the same. ... It's just that
in certain areas of the country, pollen just exploded."
Why does pollen cause allergies?
Of all the things that cause allergic reactions, pollen is the most
widespread. Why? Mainly because it's so hard to avoid.
Few people are allergic to the heavy, waxy pollen from large flowers because
it's carried by bees and other insects. But many trees and grasses use a much
more primitive form of sexual reproduction: They literally cast their pollen to
the winds so it will drift onto the plants' female sex organs.
Pollen from such trees and grasses is tiny, light, and dry -- perfect for
floating on the wind, and, unfortunately, perfect for getting inhaled into your
nose or stuck in your eye.
Once pollen sticks to your nose or eye, it releases the protein inside it.
It's this protein that triggers allergic reactions.
There are two steps to this process. First, a person has to be sensitized to
a particular pollen. The pollen protein is recognized by the immune system as a
foreign invader and it makes a particular kind of antibody -- IgE -- to fight
The second step occurs only in people already sensitized to a specific
pollen protein. When the protein hits the nose or eye, a flood of IgE
antibodies travel to mast cells in the nose. The IgE sits on the outside of
mast cells and, when triggered by pollen protein, unleashes a flood of
histamine and other factors that cause the immune responses we know as