Delayed vibratory angioedema: insights into pathophysiologic mechanisms.

Plasma histamine levels and the histologic, electronmicroscopic, and immunofluorescent analysis of skin biopsy specimens were examined during the development of vibration-induced angioedema in two patients. The reactions to vibration in these patients were characterized by (1) clinical angioedema peaking 4 to 6 hours after challenge, (2) evidence of mast cell degranulation as indicated biochemically by an early and late increase in plasma histamine and histologically by exocytosis of mast cell granules, (3) a progressive infiltration of inflammatory cells, coinciding with the peak clinical reaction, and (4) an absence of the immunoreactants IgG, IgM, IgA, C3, and fibrinogen. The reactions in both patients were morphologically and biochemically similar to the cutaneous late-phase allergic reactions that occur after IgE-mediated, antigen-provoked mast cell degranulation. These studies suggest that vibratory angioedema is a manifestation of mast cell-induced cutaneous late-phase reactions.