


Why we get nasal allergy symptoms
Allergic reactions occur when the immune system encounters and
overreacts to substances that are not generally considered harmful.
These substances are called allergens.

In people who have nasal allergies, the immune system reacts to an
airborne (inhaled) allergen by creating an antibody called
immunoglobulin E, or IgE, that is designed to fight that specific
allergen. This antibody-allergen complex attaches to certain cells in
the nasal passages and causes the release of chemicals including
histamine, which in turn cause inflammation.
The end result is nasal allergy symptoms—congestion, sneezing,
itchy nose or runny nose. Some common examples of inhaled allergens are
airborne pollens from some plants and trees, mold spores, and dog and
cat dander.
Allergies and genetics
Just like many of your physical
characteristics—such as hair or eye color and height—your susceptibility
to allergies may be inherited. However, even with a genetic tendency,
you don't automatically get allergies. Several factors must also be
present in order for a person to develop an allergic sensitivity. These
include:
- Specific inherited genes
- Exposure to the allergens you are genetically predisposed to react to
- The amount of, and length of, exposure to the allergens
For instance, even with a genetic likelihood to develop an allergy
to dust mites, it may take several years of exposure to the allergen
before allergy symptoms appear. This is why, as people age, they
sometimes develop allergies to substances in their environment.
Your likelihood of inheriting allergies
If one of your parents had allergies, you have
about a 30 percent chance of inheriting allergic tendencies. If both of
your parents had allergies, your chance of having allergies increases to
70 percent.