Question

In anaphylactic shock, the substance which causes the dilation of blood vessels and capillary leakage is

• A. Adrenaline
• B. Benadryl
• C. Albumin
• D. Histamine

Answer 1

The correct option is D Histamine

• Anaphylaxis is a severe, whole-body allergic reaction. After initial exposure to a substance such as a wasp sting toxin, the allergic child's immune system becomes sensitized to that allergen.
• On subsequent exposure to the specific allergen, an allergic reaction, which can involve a number of different areas of the body occur. Specifically, an immunoglobulin antibody protein, IgE, is produced in response to the presence of the allergen. IgE binds to the mast cells, causing them to suddenly release a number of chemicals, including histamine, heparin, serotonin, and bradykinin.
• Shock can occur when the released histamine causes the blood vessels to dilate, which lowers blood pressure; histamine also causes fluids to leak from the bloodstream. Hence, In anaphylactic shock, the substance which causes the dilation of blood vessels and capillary leakage is Histamine.

So, the correct answer is 'Histamine'.