Passive cutaneous anaphylaxis in diabetic rats

: The effect of diabetic condition on heterologous passive cutaneous anaphylaxis (PCA) reaction was studied. In alloxan diabetic rats, PCA reaction was inhibited by 68.2% of control values. The skin hyposensitivity in diabetic rats could not be attributed to a lower quantity of skin mast cells; it is suggested that alterations in the endothelial cells of the microcirculatory blood vessels decrease permeability to biologically active mast cell factors.