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Atopy is a cumulative threshold disease. Existing but subclinical
disease may be asymptomatic until exposure to an additional antigen
or irritant occurs.(1) Stress, smoking, fatigue, poor nutrition,
and illness also can add to the load. Most people who are allergic
are allergic to more than one thing. Each exposure increases the
allergy load. Symptoms appear when an individual's allergy
load exceeds his or her allergy threshold. Avoidance of as many allergens
as possible can lessen the allergic load and reduce or eliminate
symptoms. It can also eliminate the need for pharmacotherapy. But
while avoidance and other treatments can provide symptom relief,
they do not eliminate the underlying subclinical allergy.(1)
This
diagram represents a person who might be allergic to 3 things:
dog dander (allergen 1), dust mites (allergen 2), and ragweed (allergen
3).
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In situation A, a pet owner is exposed to dog dander
and dust mites but does not have symptoms because he is
below his threshold.
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In situation B, it's hay fever season
and he is exposed to ragweed. He has now passed his allergy
threshold and is experiencing symptoms. This person may think he
has seasonal allergies and become resigned to feeling miserable
at certain times of the year.
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In situation C, the person found out
what he is allergic to and reduced exposure to the family
dog. Putting dust mite covers on bedding and removing carpeting
and curtains from the bedroom reduced allergen 2 exposure. If
needed, he can also reduce his exposure to the family dog (allergen
1). Now when allergen 3 is added, the load on his system remains
below his threshold and he does not have allergy symptoms.
Elimination of symptoms is not possible for everyone. Successful
treatment depends on the severity of the allergies, number of allergen
sensitivities, and taking steps to eliminate or avoid exposure. Allergy
medications help relieve symptoms, but they do not address the underlying
cause. The first step in finding the true cause is accurate, specific
IgE testing.
REFERENCE
- ETAC Study Group. Allergic disease process: insights
into inflammatory cells and mediators. ETAC Science. 1996;7:1-12.
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