Immunohistological comparison of granulated cell proteins in induced immediate urticarial dermographism and delayed pressure urticaria lesions

Summary Urticarial dermographism and delayed pressure urticaria are two forms of physical urticaria which are well defined clinically and histologically. Previous studies have shown eosinophil granule protein deposition in urticarial reactions, including chronic urticaria, solar urticaria and delayed pressure urticaria. To evaluate and compare the involvement of granulated inflammatory cells in urticarial dermographism and delayed pressure urticaria, we studied sequential biopsies of induced lesions of urticarial dermographism and delayed pressure urticaria by indirect immunotluorescence, to detect eosinophil granule major basic protein (MBP) and neutrophil granule elastase. Biopsies from dermographic lesions at time 0.5 min, 15 min, 2h and 24 h, showed few infiltrating eosinophils, with minimal extracellular MBP deposition, and a few infiltrating neutrophils, with minimal neutrophil elastase deposition, throughout the evolution of the lesions. Sequential biopsies of delayed pressure urticaria at time 0. 20min. 6. 12 and 24h. showed eosinophil infiltration with extensive MBP deposition beginning at 20 min. and neutrophil infiltration with variable elastase deposition beginning at 20 min. Control tissue specimens from normal volunteers showed neutrophil infiltration and slight degranulation, but no eosinophil infiltrations or degranulation. Comparison of Urticaria dermographism with delayed pressure urticaria showed marked differences in the patterns of infiltration. Delayed pressure urticaria, with eosinophil and neutrophil degranulation, was strikingly similar to the IgE‐mediated late phase reaction. In contrast, eosinophil and neutrophil involvement in urticarial dermographism was minimal. Considering the extent of eosinophil granule protein deposition and the biological activities of the eosinophil granule proteins, the findings in delayed pressure urticaria point to an important pathophysiological role of eosinophils in the disease.