SKIN SENSITIVITY TO ALLERGEN DOES NOT ACCURATELY PREDICT AIRWAY RESPONSE TO ALLERGEN

Background: Allergen challenge of the asthmatic airway has become wide ly applied in the study of allergic asthma in humans. Skin sensitivity correlates with inhaled sensitivity in some populations. Skin test ti tration has been proposed as a useful tool to guide the selection of i nitial allergen concentration. Objective: To determine the relationshi p between skin test sensitivity and inhaled reactivity to allergen. Me thods: We examined the relationship between skin test and inhaled reac tivity in 22 allergic asthmatic subjects. Methacholine bronchoprovocat ion was performed using a standardized tidal breathing technique. Pric k skin test titrations were done using serially diluted lyophilized an tigen extracts reconstituted in normal saline from 1:100,000 to 1:10. Inhaled allergen challenge was routinely performed in the morning usin g the same allergen employed in skin test titration. Results: There wa s no correlation between skin test threshold and the inhaled concentra tion required to produce a 20% fall in FEV1 (r = 0.07; P = .78). If su bjects who manifested marked cutaneous reactivity tie, skin reactivity at dilutions greater than 1:10,000) were excluded from analysis, ther e was a significant correlation between cutaneous and inhaled reactivi ty (r = 0.84; P < .001). Conclusion: While a correlation between skin test threshold and inhaled reactivity is present in some subjects with allergic asthma, the relationship is inconsistent.