The Pathogenesis of Chronic Spontaneous Urticaria: The Role of Infiltrating Cells.

Chronic spontaneous urticaria is characterized by a perivascular non-necrotizing cellular infiltrate around small venules of the skin. It consists primarily of CD4(+) lymphocytes, a prominence of the Th-2 subtype but also Th-1 cells, with Th 17 cell derived cytokines elevated in plasma. There are also neutrophils, eosinophils, basophils, and monocytes. Chemokines derived from mast cells and activated endothelial cells drive the process. While the role of the cellular infiltrate has not previously been addressed, each constituent contributes to the overall pathogenesis and responsiveness to steroid, in particular, focus attention on its importance since short-term steroids do not affect autoimmunity or degranulation of mast cells, and act on margination of cells along the endothelium and chemotaxis to enter the surrounding dermis. In this review we address each cells contribution to the overall inflammatory response, as it is currently understood, with a view toward development of therapeutic options that impede the function of critical cells and/or their secretory products.