What is the role of skin testing in the workup of asthma?

Updated: Oct 07, 2019
  • Author: John J Oppenheimer, MD; Chief Editor: Michael A Kaliner, MD  more...
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Answer

Answer

Skin testing is one of the most useful ways of determining specific allergen sensitivity. Such tests for allergen-specific IgE are necessary if the clinician is to provide informed advice to patients about allergen avoidance techniques; they are also necessary for planning allergen immunotherapy regimens.

Skin tests have the advantage of being immediately available and visible to patients, which may reinforce to patients the need for environmental control and, possibly, immunotherapy.

Skin testing is recommended for antigens to which the patient is exposed rather than testing with a standard panel. Skin test findings have a fairly high false-positive rate but a very good negative predictive value. Thus, a positive test result does not mean that a patient is currently being exposed to an allergen or that he or she will react to it in a natural exposure. A negative test result generally rules out the possibility that an allergen is having an impact on the patient’s asthma. [18]  It is important to determine if a positive test result is clinically relevant (history of symptoms with exposure/timing).

Antihistamine medications and tricyclic antidepressants (TCAs) interfere with allergy skin testing; short courses of oral glucocorticoids at moderate doses do not.

Testing should not be performed during an asthma exacerbation, and the testing site should be equipped for the treatment of rare, life-threatening reactions.

Skin testing is performed with controls (eg, histamine and saline) to avoid false-positive (dermatographism) or false-negative results. Identification of allergen triggers can assist in formulating an environmental control strategy, titration of therapy (ie, seasonal exacerbation), or an immunotherapy regimen.


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