Allergic Rhinitis & Immunotherapy: Hope or Hype
Although accreditation for this CE/CME activity has expired, and the posttest is no longer available, you can still read the full article.
Expires March 31, 2015
–
Allergic rhinitis (AR), one of the most familiar complaints seen in primary care, is a common immunologic condition that occurs in genetically predisposed patients. AR is routinely treated through allergen avoidance and pharmacologic therapy. When these measures fail, however, immunologic treatment may be indicated. This review of AR and its treatment focuses on injection and oral immunotherapy.
ALLERGY TESTING
In order to distinguish between AR and NAR and to direct treatment toward specific allergen avoidance and immunotherapy, providers have the choice of ordering in vitro blood IgE testing (to measure the antibodies that mediate an allergic response) or in vivo allergy skin testing (to measure the immune response to allergens that induces an allergic atopic reaction). Allergy testing is not a contemporary concept; the first allergy testing was documented in 1656 when Pierre Borel applied egg to a patient’s skin, which exhibited an allergic reaction.2
Allergy skin testing consists of applying multiple allergens to the skin of the patient’s forearms via tiny pinpricks while watching for immediate hypersensitivity reactions. The test begins with the placement of a drop of histamine to serve as a control. If after 10 minutes of watchful waiting the patient develops a reaction to the histamine (a positive test result), it is appropriate to test for antigens by placing drops of suspected allergen extracts on the skin.
After a period of time (usually 20 to 30 minutes), the area is inspected for allergic reaction. An immediate (early phase) wheal and flare (surrounding erythema) reaction may develop. This positive reaction indicates the presence of a mast cell–bound IgE antibody specific to the tested allergen. The size of the reactions is measured in millimeters, allowing for comparison to the histamine control.
A list of the commonly tested antigens in Arizona, as an example, is shown in Table 3. Antigens vary geographically and even from practice to practice. For up-to-date information on pollen counts by region, visit the American Academy of Allergy Asthma & Immunology Web site (see “Pollen Counts”).
On the next page: Patient selection and allergy immunotherapy >>
