NSAID intolerance in chronic idiopathic urticaria: A study of its relationship with histamine-releasing activity of patients' sera.

BACKGROUND about one fourth of patients with chronic idiopathic urticaria (CIU) experience flares of hives after taking chemically unrelated nonsteroidal anti-inflammatory drugs (NSAID). The reasons for such intolerance are still elusive. OBJECTIVE this study aimed to investigate NSAID intolerance in patients with CIU in view of the in vivo and in vitro histamine releasing activity of their sera. METHODS 117 adults (M/F 41/76) with CIU underwent intradermal test with autologous serum, and the ability of their sera to induce histamine release from normal blood donors was evaluated. NSAID intolerance was ascertained by careful interview. RESULTS overall, 32/117 (27 %) patients reported NSAID intolerance. The prevalence on NSAID intolerance did not differ in the three subgroups: negative on both in vivo and in vitro tests (9/36; 25 %), positive or intradermal test but negative on basophil histamine release assay (16/58; 28 %), or positive on both in vivo and in vitro tests (7/23; 30 %). CONCLUSION in patients with CIU intolerance to NSAID does not depend on the mechanism of histamine release.