What are allergies?
Allergic disorders affect an estimated 1 in 5 adults and
children (40 to 50 million people) and are the sixth leading cause
of chronic illness in the United States, according to the Allergy
Report from the American Academy of Allergy, Asthma and Immunology
(AAAI).
Allergies are the immune system's inappropriate response
to a foreign substance. Exposure to what is normally a harmless
substance, such as pollen, causes the immune system to react as if
the substance were harmful. Substances that cause allergies are
called allergens. Most allergies result from a combination of
inheritance (genes) and environmental exposures (pollens, animal
danders, etc.). Being exposed to allergens at certain times when
the body's defenses are low or weak, such as after a viral
infection or during pregnancy, also may contribute to the
development of allergies.
When you come into contact with an allergen, you may experience
symptoms of allergic rhinitis (hay fever) including sneezing,
congestion, itchy, watery nose and eyes and/or asthma symptoms such
as wheezing, chest tightness, difficulty breathing and
coughing.
What is an allergic reaction?
A hypersensitive response, or allergic reaction, is the result
of the interaction among the allergen itself, mast cells and
immunoglobulin E (IgE). The result is a release of inflammatory
chemicals that can cause swelling of tissues, itching, engorgement
of blood vessels, increased secretions and bronchospasm (tightening
of muscles that surround the airways).
If the allergen is in the air, the allergic reaction will occur
in the eyes, nose and/or lungs. If the allergen is ingested, the
allergic reaction may primarily occur in the mouth, stomach and
intestines.
Types of allergens causing Allergic Rhinitis (hay fever)
The most common allergens are pollens and dust mites. Allergic
rhinitis, or hay fever, is the allergic response to pollen. It
causes inflammation and swelling of the lining of the nose, as well
as the protective tissue of the eyes (conjunctiva). Symptoms
include sneezing, congestion and itchy, watery eyes. Treatment
options include over-the-counter and prescription oral and topical
medications. These medications include antihistamines, intranasal
cromolyn, intranasal steroids, oral antileukotrienes, oral
decongestants, and others. Among the most effective strategies to
reduce allergic rhinitis symptoms is avoidance.
Avoiding pollen exposure by staying indoors when pollen counts
are high, closing windows and using air conditioning will help
reduce symptoms. Avoidance of indoor allergens such as dust mites
and mold spores entails measures to reduce indoor humidity. Dust
mite exposure can also be reduced by mattress/box spring and pillow
encasement, and washing all bedding in hot cycle frequently.
Avoiding pets is a challenge for many patients, but can be a very
important factor in improving symptoms of allergic rhinitis and/or
asthma. When avoidance measures combined with regular use of
medications is not effective, not feasible or not desirable,
immunotherapy (allergy shots) may be considered.
- Pollens--Pollens are microscopic particles
released in to the air by trees, grasses and weeds. When these
particles are inspired, people who have inherited the potential to
make allergic responses in their immune system may become
sensitized. When they are subsequently re-exposed to the same
pollen, they may experience symptoms of allergic rhinitis.
- Dust mites--Dust mites are microscopic insects
that live in dust and in the fibers of household objects not
frequently laundered, such as pillows, mattresses, carpet and
upholstery. Dust mites require warm, humid areas. The symptoms of
dust mite allergy are similar to those of pollen allergy, and also
can produce symptoms of asthma such as wheezing and coughing. To
help avoid dust mite allergens, try using dust mite covers
(air-tight plastic/polyurethane covers) over pillows, mattresses
and box springs. Also, remove carpeting or vacuum frequently using
a vacuum cleaner with high efficiency filters. Treatment frequently
also includes medications and/or allergen immunotherapy (allergy
shots).
- Molds--Molds are parasitic, microscopic fungi
with spores that are also released in the air -- like pollen.
Mold can be found in damp areas, such as the basement or bathroom,
as well as in the outdoor environment in grass, leaf piles, hay,
mulch or under mushrooms. Mold spores peak during hot, humid
weather.
- Animal dander--The proteins secreted by sweat
glands in an animal's skin, which are shed in dander, and the
proteins present in an animal's saliva cause allergic
reactions in some people. Treatment involves avoiding exposure as
much as possible.