What Is An Allergy?

There’s a lot of talk about allergies. But just what
is an allergy and what causes them? Why do some people
have them while others don’t? And why are people with
one allergy more inclined to have many?

The immune system is set up to protect our bodies from
harmful, foreign substances. Like viruses and bacteria
(dirt and germs). Sometimes the immune system doesn’t
develop properly or is just oversensitive and doesn’t
react right.

In these cases, it reacts to things that aren’t
harmful and don’t usually cause people any problems.
These things are called allergens. The term allergens
is just an easier way to say "things that cause
allergies".

When the oversensitive or improperly developed immune
system sees these allergens, it sends out chemicals
like histamine. It’s the histamines that cause the
symptoms that are common with allergies.

Symptoms like itching, watery eyes, runny nose,
swelling, hives or rashes. Different people have
different symptoms, but the causes are the same.

The symptoms that are displayed depend on the part of
the body the allergen comes in contact with. Allergens
that are breathed in, like pollen or dust cause
coughing or wheezing, stuffy or runny noses and an
itchy nose and throat.

Plant allergies usually come in contact with the skin,
so they cause rashes.

Food allergies usually result in nausea, vomiting,
stomach pains or in severe cases, life threatening
reactions. Drug allergies tend to involve the entire
body, so they have a variety of symptoms.