Histamine causes fluids and proteins to leak out of the capillaries.
FYI: When capillary leakage occurs in the nasal mucous membranes, nasal congestion occurs. When capillary leakage occurs in the skin, edema, wheals, or hives are produced. Itching and pain occur because histames irritates sensory nerve endings. The erythema and edema produced by histamine in the skin ar known as the Response of Lewis