Simultaneous occurrence of chronic autoimmune urticaria and non-allergic asthma: a common mechanism?

Chronic urticaria is now considered as an autoimmune disorder due to histamine-releasing autoantibodies in 40-50% of cases. These histamine releasing-autoantibodies directed against the high affinity IgE receptor or against IgE can be detected in vivo by autologous serum skin test (ASST) or in vitro by a functional assay employing basophils. ASST positivity has been found also in patients with non-allergic asthma, but its relevance to the disease mechanism remains to be defined. Here, we report two women aged 43 and 75 years who complained simultaneous occurrence of chronic urticaria and asthma. Circulating histamine-releasing factors were detected in both patients by ASST and basophil histamine release assay whereas other possible causes of urticaria and asthma were excluded by clinical and laboratory investigations. The elder woman had associated autoimmune thyroiditis. We suggest that circulating histamine-releasing factors, probably represented by histamine-releasing autoantibodies, might be involved in the pathophysiology of both chronic urticaria and asthma.