Abstract: Insect stings are an important cause of anaphylaxis. Anaphylaxis can also occur from insect bites but is less common. Insect venoms contain several well-characterized allergens that can trigger anaphylactic reactions. Effective methods to diagnose insect sting allergy and assess risk of future sting reactions have been developed. Management strategies using insect avoidance measures, self-injectable epinephrine, and allergen immunotherapy are very effective in reducing insect-allergic patients' risk of reaction from future stings. Diagnostic and management strategies for patients allergic to insect bites are less developed.
Key Words: anaphylaxis, insect reaction, insect venom
Insect stings by members of the Hymenoptera family have caused human deaths since at least the time of the Ancient Egyptians and are currently responsible for at least 40 deaths from allergic reactions per year in the United States. The prevalence of insect sting allergy is estimated to be between 0.5 and 3%, and people who have previously experienced generalized allergic insect sting reactions are at increased risk for reactions from future stings. Effective management strategies using allergen immunotherapy can greatly reduce the risk of future anaphylactic reactions and their associated morbidity and mortality. (1-6)
Insect bites can also cause allergic reactions, but scientific knowledge about insect bite allergy is limited. Reactions have most commonly been reported after bites from mosquitoes and other flies and from Triatoma bugs. (7) Unfortunately, management strategies to reduce the risk of future insect bite reactions are less well developed and less effective than for insect sting allergy.
The three families of stinging insects in the order Hymenoptera are Vespidae, Apidae, and Formicidae. (5) Yellow jackets, wasps, and hornets all belong to the Vespidae family (vespids); honeybees and bumblebees belong to the Apidae family (apids); and stinging ants belong to the Formicidae family (formicids). In most areas of the United States, yellow jackets are the leading cause of allergic insect sting reactions; however, in many areas of the South, fire ants (Fig. 1) or wasps (Fig. 2) are the leading causes of these reactions. (1), (4), (5)
Yellow jackets are very aggressive insects that nest in the ground, hollow logs, wall tunnels, and caverns, where they can be easily disturbed. They are attracted to food, drinks, picnic areas, and garbage.
Hornets, which are close relatives of yellow jackets, form large paper nests in shrubs and trees and are also very aggressive. The two main species in the United States are the baldfaced (or white-faced) hornet and the yellow hornet. Hornets are also very aggressive, especially when near the nest.
Wasps form honeycomb paper nests under the eaves of houses and other buildings and in trees and shrubs. The insects can be seen on the surface of the nest.
Domestic honeybees are less aggressive and usually sting only when disturbed; however, persons who disturb their hives may suffer massive numbers of stings. Their hives, which are frequently located in hollow trees or logs or in buildings, are quite large and can contain thousands of bees. After stinging the victim, they usually leave the barbed...
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