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The phylum Arthropoda is the largest division of the animal kingdom. The
phylum includes insects (bees, wasps, hornets, flies, mosquitoes, bedbugs,
fire ants, caterpillars, fleas), arachnids (spiders, scorpions,
chiggers, ticks), and crustaceans (shrimp, lobsters, crabs). Venomous
bites and stings from arthropods are a significant worldwide problem.1 In
the U.S., the American Association of Poison Control Centers reported
almost 50,000 cases of exposures to arthropods in 2008.2 Some
of these were listed as resulting in major or severe reactions,
including severe pain, neurotoxicity, or other signs and symptoms.
Fatalities among these exposures are rarely reported to poison centers
and usually result from allergic reactions to Hymenoptera stings.
Clearly, these numbers are the tip of the iceberg. Toxic reactions
to multiple stings by members of the order Hymenoptera and severe
systemic allergic reactions to one or more stings or bites of other
insects, such as deerflies, blackflies, horseflies, and kissing
bugs, can all present as emergency, life-threatening situations
(Table 205-1).3 Other arthropod
bites and envenomations merit review either because they cause specific
organ system toxicity or because they can result in transmission
of infectious disease. This chapter discusses the more common and
serious arthropod bites and envenomations encountered by emergency
physicians.
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The Hymenoptera are the most important venomous insects known
to humans, and more fatalities result from stings by these insects
than by stings or bites by any other arthropod. There are three
major subgroups or superfamilies of medical importance: (1) Apidae,
which includes the honeybee and bumblebee; (2) Vespidae, which includes
yellow jackets, hornets, and wasps; and (3) Formicidae, or ants
(Figure 205-1).
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Bees and Wasps (Apidae
and Vespidae)
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Apids, such as honeybees and bumblebees, are
usually docile, ...