<prompt> Lewis triple response is caused due to:HistamineAxon reflexInjury to endotheliumIncreased permeability  <response>: Lewis triple response is caused due to Histamine When histamine is injected intradermally it causes the triple response consisting of: Red spot: Due to capillary dilatation. Wheal: Due to exudation of fluid from capillaries and venules. Flare: Redness in the surrounding area due to aeriolar dilation mediated by axon reflex. A, Triple response elicited by firm stroking of skin of forearm with a pencil. B, Diagrammatic view of microscopic features of triple response of the skin 