Chronic idiopathic urticaria: Possible contribution of histamine-releasing factor to pathogenesis

Background: Histamine-releasing factor was recently shown to be clinically relevant in allergic rhinitis and asthma. HRF could also be involved in the pathogenicity of chronic idiopathic urticaria (CU). The purpose of this study was to investigate the role of HRF in the pathophysiology of CU. Methods: Blisters were induced on lesional and nonlesional skin of 12 patients with CU and on normal skin of five control subjects. HRF activity and histamine content were measured in all samples recovered from each skin site. Results: Significantly more HRF was found in blister fluids from lesional skin of patients with CU as compared with nonlesional skin and skin of control subjects. In addition, histamine content in blister fluids from affected skin of patients with CU was significantly higher in comparison with both nonlesional skin of patients with CU and skin of control subjects. HRF activity was also higher in blister fluids from nonlesional skin of patients with CU than that of control subjects, in spite of equivalent histamine content. Conclusion: These data suggest that the inflammatory reaction found in CU disease is associated with the cutaneous release of HRF.