When your nose is runny and eyes are itchy you
probably are just interested in relief; not in why
this reaction is happening. Sometimes though, it is
helpful to know the detail of how a medical condition
is produced especially when it is one that is chronic
and going to afflict you the rest of your life. Allergy
is one such condition. People with allergies have
genes that make them more likely to develop a bodily
reaction to various substances they are exposed to.
The body's immune system is the main protective mechanism
to maintain health. It identifies and fights off bacteria,
viruses, parasites, cancer cells, food and any foreign
protein substance. Lymphocytes are one type of white
cell in your blood and they are a major component
of the immune system. As soon as a foreign protein
enters the body, the lymphocytes identify the protein,
fingerprint it and determine if it belongs to this
body or not. "Lymphocytes act like traveling
customs agents. Everywhere they go, they are busy
checking the passports of every cell they encounter.
Whenever they discover a cell that seems threatening,
they immediately begin countermeasures against it.
The biochemical process behind these countermeasures
is amazing! (1)
Allergies result when this immune system is hypersensitive,
overreactive. When the system misidentifies harmless
proteins as serious enemies and then reacts out of
proportion to the threat, you get symptoms from this
major bodily battle. Those symptoms may be mildly
annoying or a major illness. Usually for your immune
system to overreact like this you must have a genetic
tendency for it.
After the lymphocyte identifies the foreign protein
(antigen) it goes back to a lymph node where it changes
into a different type of white blood cell (mast cell).
The mast cell manufactures a chemical called an immunoglobulin
that is exactly configured like a laser ray to destroy
the specific protein that the lymphocyte identified
in the first place. Of the different immunoglobulins
(IgA, IgD, IgE, IgG, IgM), Ig E is the class that
forms an allergic reaction. They attach to other white
blood cells in what is called the sensitizing exposure,
When the protein comes into the body again, at least
7-10 days after the sensitizing reaction, the IgE
primed mast cells release many chemicals including
histamine that try to destroy the "invading"
protein. Histamine lowers the local blood pressure
and causes itching and swelling . It can also cause
wheezing, an itchy, runny nose, nausea, vomiting or
diarrhea. That is why "anti- histamine"
drugs are used to treat allergies.
Specific allergies can be identified either by a
blood test for IgE or by a scratch test in which the
suspected allergen is "scratched" into the
skin to see if the body reacts to it with redness
and swelling. A problem with specific identification
of allergies, however is what is called cross-reactivity.
Sometimes proteins of different but similar substances,
e.g., shrimp and crab meat, can both cause an allergic
response even though the body had previously been
exposed to only one of them. Even so, allergen identification
is very important so that you can avoid the offending
allergen in the first place.
Now why is it important to know the mechanism of
action for allergies? If there is a genetic disposition
for your body to form allergic responses, there is
not much you can do - correct? No. You basically have
two practical choices for self-care. Identify the
causative agents so you absolutely avoid them and
treat with anti- histamines for mild but annoying
allergic reactions. Fortunately there is a self home
test for food allergies, Food allergy test kit, and
also one that tests for grasses, molds, dust and cat
allergies along with some common food allergies such
as milk, eggs and wheat, MyAllergyTest. For other
tests you will have to have a doctor's order and have
a blood drawn and sent to a special laboratory. If
you are having serious reactions, see an allergist
for allergen identification and treatment.
One last tip. The gold standard for diagnosing allergies
are the scratch test sets applied in the allergist's
office. Many times, however, you may not want to suffer
the reactions you get during testing or you may fear
causing a new allergy by sensitizing through your
skin to a new substance you are not already allergic
to. The allergy doctor may prefer the scratch tests
because they are more accurate but you can ask to
have the blood test done instead, with subsequent
scratch testing if needed, to narrow down the specific
allergen from a general group of substances.
|
