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Question 10#

A 32-year-old woman with a history of migraine headaches on prophylactic propranolol experiences a severe anaphylactic reaction following a sting from a yellow jacket. She is treated successfully with parenteral epinephrine and is dismissed from the hospital.

What is the best recommendation for prevention of recurrent hospitalizations? 

A) Pursue desensitization injections against Hymenoptera species
B) Discontinue beta-blockers
C) Avoid exposure to bees as well as wasps
D) Carry an epinephrine self-injector (Epi-pen) with her during outdoor activities
E) Take loratadine 10 mg daily

Correct Answer is D

Comment:

Approximately 40 deaths per year occur as a result of Hymenoptera stings. Additional fatalities undoubtedly occur and are unknowingly attributed to other causes. Both atopic and nonatopic persons experience reactions to insect stings. The responses range from large local reactions with erythema and swelling at the sting site to acute anaphylaxis.

Although each of the first four recommendations might be beneficial, the most important measure is for this patient to keep an epinephrine self-injector with her during activities where Hymenoptera species might be encountered. These devices are very effective when used properly. Desensitization injections are probably effective, although they carry some risk of anaphylaxis (albeit in a controlled setting). Beta-blockers increase the risk of anaphylaxis and impair response to epinephrine if an allergic reaction should occur. The venom of honeybees (apids) cross-reacts moderately with that of wasps (vespids), although the latter are the most dangerous species. Antihistamines have not been shown to block anaphylaxis. Numerous mediators other than histamine are present in mast cell granules. The majority of fatal reactions occur in adults, with most persons having had no previous reaction to a stinging insect. Reactions can occur with the first sting and usually begin within 15 minutes. Enzymes, biogenic amines, and peptides present in the insects’ venom are the sensitizing allergens. Venoms are commercially available for testing and treatment. Venom immunotherapy is indicated for patients with a history of sting anaphylaxis and positive skin tests. Although epinephrine self-injectors can be lifesaving; they are contraindicated in the presence of ischemic heart disease.