An increased prevalence of atopy has been observed in patients with intolerance of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs).To investigate total and mite-specific immunoglobulin (Ig) E in serum from patients with hypersensitivity to NSAIDs and healthy controls.Patients who reacted to 2 or more chemically unrelated NSAIDs with urticaria and angioedema, confirmed by a double-blinded provocation test with aspirin, were skin tested with inhalant allergens. Total and specific IgE to Dermatophagoides pteronyssinus (Dp) and Blomia tropicalis (Bt) in the serum was quantified by enzyme-linked immunosorbent assay (ELISA) in patients and a control group of healthy blood donors.One-hundred-and-fourteen patients and 74 controls were studied. Skin tests were positive in 95 patients (83.3%). Total mean IgE levels were 107.1 (91.3) IU/mL in controls and 161.0 (150.8) IU/mL in patients (P = .006). Mean (SD) levels of IgE to Dp were 0.210 (0.17) optical density (OD) units in controls and 0.473 (0.65) OD units in patients (P = .001). Levels of specific IgE to Bt were 0.230 (0.20) OD units in controls and 0.522 (0.8) OD units in patients (P =.0001). Positive ELISA results for IgE to Dp were found for 29.6% of controls and 70.4% of patients (P =.0001); the corresponding percentages for Bt were 32.4% of controls and 67.6 % of patients (P = .0001).Cross-reactive patients with NSAID-induced urticaria and angioedema exhibit an increased prevalence of sensitization to Dp and Bt and increased total serum IgE. Further research is necessary to determine the reasons for this association.