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Allergy-like Symptoms: a Diagnostic Challenge
Diagnosis of common illnesses often presents a major challenge to the primary
care clinician because symptoms can overlap between allergic and non-allergic
causes. Approximately 50% of all adults with rhinitis do not have allergic
rhinitis (AR).1 In
children, underlying atopic sensitivities account for up to 30% of common illnesses,2 yet,
as with adults, a correct diagnosis of allergic disease based solely on history
and physical yields a correct diagnosis only half the time.3 While
symptoms alone yield few clues to the underlying etiology or pathology of
atopic disease, allergy can be objectively confirmed by the presence of IgE
antibodies.4 Experts
agree that accurate diagnosis of allergy-like symptoms requires objective evidence.3,4 Allergic
rhinitis (AR) offers a compelling case in point.
The AR Example: Diagnostic Precision Aids
Treatment Selection
 A recent study suggested
that AR is over-diagnosed using patient history and
physical alone. Among patients prescribed non-sedating
antihistamines, 65% of those tested for IgE antibodies
were found to be not allergic.5 As
a result, these patients spent money on expensive
medications that didn’t treat the cause of
their symptoms. ImmunoCAP blood testing can help
clinicians avoid such missteps by enhancing the diagnosis
of allergy-like symptoms. With this test, you can
know for sure what’s causing the symptoms before
prescribing medication.
Cumulative Threshold
Patients are often polysensitized.6 As
a result, symptoms of atopic illness are often triggered
only after exposure to multiple allergens. The patient who
is sensitized to more than one allergen crosses the symptom
threshold only after a cumulative allergic load has been
reached.7,8 In
those patients who are monosensitized, allergic symptoms
will occur only after sufficient exposure to that one allergen.
Patients can find resolution of their symptoms through the
avoidance of one or more allergens in order to diminish the
cumulative load to a level at which symptoms don’t
occur.9,10 With
quantitative specific IgE blood test results, the primary
care clinician can tailor avoidance measures to reduce cumulative
allergic load, select effective treatments, and make an appropriate
referral.
Atopy is a cumulative threshold disease. Existing but subclinical
disease may be asymptomatic until exposure to an additional
antigen or irritant occurs.7,8 Treatment
effectively alleviates symptoms,9,10 although
it does not eliminate the underlying subclinical allergy.
Value of a negative result
A negative result from specific IgE blood testing can be as illuminating as
a positive result, since knowing that allergy is not present allows the continued
search for etiology. Confirmation or repudiation of the presence of atopy
can greatly affect subsequent diagnosis, leading to more appropriate use
of prescription medications and other treatment options.
In confirmed allergic disease, the clinician can employ avoidance
measures and other allergy-based therapies (such as non-sedating
antihistamines).10 In non-allergic disease, meanwhile, the
clinician can consider such medications as intranasal corticosteroids,
antibiotics, and decongestants.10
Determining the exact etiology of upper respiratory symptoms can
help you get your patients on the right treatment path from
the very beginning, reducing repeat office visits and ensuring
the appropriate use of antibiotics and other prescription
medications. With evidence-based decision making using the
ImmunoCAP Specific IgE blood test, you can approach treatment
decisions with confidence.
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