Food Allergy Quiz

See Management. Option C is correct. Anaphylaxis is a life-threatening allergic reaction in which mast cells release histamine and other mediators, causing vasodilation (widening of the blood vessels), leaky vessels, low blood pressure, bronchoconstriction (narrowing of the airways) and swelling of the throat. Adrenaline (epinephrine) is the only drug that reverses all of these effects quickly. It acts on alpha-receptors to constrict blood vessels and reduce swelling, and on beta-receptors to widen the airways and strengthen the heartbeat. It is given by the intramuscular route, ideally into the front and outer part of the thigh (the anterolateral thigh), and repeated after five minutes if there is no improvement. For an adult the dose is 500 micrograms (0.5 mL of the 1 in 1000 solution). People with a known severe allergy are taught to carry an adrenaline auto-injector (such as an EpiPen), a pre-loaded pen that delivers a fixed dose into the thigh, and to use it at the first sign of a severe reaction without waiting to see if it settles. After adrenaline, call for help, lie the patient down, give oxygen and fluids, and monitor them.

• Drug: intramuscular adrenaline is the only drug that quickly reverses all the effects of anaphylaxis
• Site: the front and outer part of the thigh
• Adult dose: 500 micrograms (0.5 mL of the 1 in 1000 solution), repeated after five minutes if there is no improvement