Nasal polyposis: prevalence of positive food and inhalant skin tests.

OBJECTIVES: To investigate the etiology of nasal polyps and its relationship to allergy. The prevalence of positive food and inhalant skin tests in patients with nasal polyps and nonatopic controls was compared. STUDY DESIGN AND SETTING: Prospective controlled study in tertiary referral rhinology clinic. RESULTS: Seventy percent (70%) of the patients with nasal polyps had positive skin tests to an average of four foodstuffs, compared to 34 percent of controls (P = 0.006). Only 35 percent of the nasal polyp patients also had positive inhalant skin tests. Overall, the prevalence of positive inhalant skin tests was similar in the nasal polyp patients and controls. CONCLUSIONS: These findings suggest that the positive skin tests to foods are not merely a reflection of the general atopic status of patients with nasal polyps. It may be that non-IgE-mediated hypersensitivities, such as to ingested foods, play a role on the basis of a significant number of patients with positive intradermal skin tests to foods. SIGNIFICANCE: Evaluation of the allergic status of patients with polyposis is important. Dietary manipulation may be indicated, though its role needs further investigation.