ALLERGIC RHINITIS: Outcomes of Immunotherapy on Symptom Control

Because the effectiveness of immunotherapy does not occur independently of diagnostic methodology, a brief comment about allergy testing is germane to this discussion. The techniques of in vivo diagnostic allergy testing rely on the reactivity and sensitivity of mast cells that have been sensitized with specific IgE to reflect allergen sensitivity. The antigens may be applied as a challenge test in a controlled fashion directly upon nasal, oral, conjunctival, bronchial, or gastrointestinal mucosa. In the clinical setting, antigen more commonly is applied directly onto or into the skin in the form of scratch, prick, or intradermal tests. Skin tests have represented the primary diagnostic tool in IgE-mediated allergy, and have provided useful, confirmatory evidence for specific allergy, the diagnosis of which has been made on clinical grounds. Skin test techniques share the characteristics of simplicity, rapidity of performance, high sensitivity and specificity when properly performed, and low cost. Recent refinements in skin testing strategies have resulted from the quest for validity and reproducibility, and for quality control and assurance. Quantitation of skin test reactivity, whether by prick or intradermal, but particularly by intradermal testing that uses a dilution-titration technique, provides the most accurate assessment of the individual's hypersensitivity. Only those skin tests that can quantitate the sensitivity of the patient to each individual allergen will provide the information necessary to formulate a treatment program that gives optimal therapeutic results. 7,33 For an antigen to elicit a beneficial immunologic response, it must be given in high enough doses to stimulate a therapeutic response. Thus, skin testing methodology has a direct bearing upon the methodology of immunotherapy. Having said this, our attention will now be focused upon immunotherapy techniques, particularly newer research in oral (OIT), sublingual (SLIT), and local nasal (LNIT) immunotherapy.