The insects most commonly associated with triggering severe allergic reactions belong to the Hymenoptera order. Members include bees, wasps, yellow jackets, hornets, and ants, including the fire ant, an increasingly common, harmful pest that is spreading throughout the United States, where it is now the leading cause of insect stings.

Although you can take steps to avoid insect stings, you should also know what to do if someone is stung.

A Growing Threat

It is believed that fire ants entered the United States via steamships bringing agricultural products from South America to Mobile, Alabama, in the 1930s. Once in the United States, northern frosts and western deserts proved effective barriers to widespread fire ant migration for many years. However, recent warm, wet weather conditions, including the El Ni'o weather system of 1998, seem to have helped the ants advance north and west. They now live in more than 260 million acres and pose a serious health risk to humans, wildlife, and domesticated animals.1

Reactions to fire ant stings range from localized skin itching and swelling with pussy formations, to severe, life-threatening anaphylaxis.

Hymenoptera Members7

Fire Ants

Appearance: Usually 1/4" long; bright reddish-brown in color, can be dark brown to black

Nest: Mounds up to 18" high, 3' wide above ground, with underground tunnels

Range: As far north as Nevada in the West and Washington, DC, in the East

Behavior: Very aggressive territorial behaviors; attack in swarms with little warning or provocation

Stings: Can sting up to 7 or 8 times; causes burning, itching, pustules

Honey Bees

Appearance: 1/2" long; rounded, hairy, dark brown body with bright yellow markings

Nest: Hives in beekeepers' boxes, bushes, trees, building niches

Range: Worldwide

Behavior: Not terribly aggressive; sting only when challenged directly

Stings: Can sting only once, then lose stinger and die

Africanized Honey Bees

Appearance: 1/2" long; rounded, hairy, dark brown body with bright yellow markings like the honeybee

Nest: Honeybee hives, or any partially protected site (e.g., old farm machinery, fences, house exteriors)

Range: Spreading from the Southwest to more populated areas

Behavior: Very aggressive, temperamental, easily provoked and fiercely protective of territories up to a half-mile radius

Stings: Can sting only once, like the honeybee, but attack in swarms

Yellow Jackets

Appearance: 1/2- to 3/4" long; black with yellow markings

Nest: Papery nests in the ground or in wall crevices

Range: Worldwide

Behavior: Versatile and persistent pests. Not as easily provoked as fire ants or killer bees, but highly aggressive?particularly as weather cools in the late summer or early fall

Stings: Can use stinger more than once

Hornets

Appearance: Up to 1" long; black or brown with hints of yellow, white or orange

Nest: Brown or gray football-shaped hives of a papery substance high above ground level

Range: Throughout North America

Behavior: Extremely protective of their nest; more aggressive than honeybees but not as feisty as the fire ant or killer bee

Stings: May sting repeatedly without losing stinger

Wasps

Appearance: Elongated bodies up to 1" long; black, brown or red with yellow markings

Nest: Exteriors of buildings, woodpiles and shrubs

Range: Throughout North America

Behavior: Aggressive, but not as easily provoked as fire ants or killer bees

Stings: Can sting more than once

* All insect coloring and size is highly variable, and one cannot rely upon visual identification for testing and treatment.

Avoiding Stings

The best way to avoid stings is to minimize contact with stinging insects. Simple steps that people can take to avoid attracting and provoking stinging insects when outdoors include:

Refraining from wearing brightly colored clothing or sweet-smelling cosmetics

Keeping food and garbage covered

Wearing shoes to guard against stepping on insects

Keeping arms and legs covered during activities (such as gardening, hiking) that may expose you to stinging insects

Refraining from swatting or crushing insects

Steering clear of areas where insects have nested

Stinging insects attack when their nests are in jeopardy; people who find nests, hives, or fire ant mounds on their property may wish to consult a professional pest control expert to determine whether eradication of the nest or insects themselves is appropriate.

What to Do if Someone Is Stung

When someone is stung you should:

Remove any stingers

Check for signs of an allergic reaction

Treat allergic reactions immediately

Remove any stingers

Stingers left behind by bees should be removed immediately to minimize the amount of insect venom the sting delivers. It is important to remove the stinger in a sweeping motion'as with the edge of a credit card?instead of using tweezers to pull it out. A sweeping motion is less likely to break the stinger or push remaining venom from the stinger into the sting site (which can happen if you squeeze the stinger or try to pull it out).

Check for signs of an allergic reaction

A normal response to an insect sting is swelling, pain, and redness around the site of the sting or bite. Typically, washing the sting site with soap and water, and then applying ice to reduce the swelling is sufficient to treat a local reaction. However, physicians may prescribe antihistamines or corticosteroids to minimize discomfort if swelling is pronounced or if the location of the sting makes it especially uncomfortable.

When a person is allergic to an insect sting, the reaction is typically much more widespread and may include anaphylactic symptoms such as:

Itching and hives

Swelling of the throat or tongue

Difficulty breathing

Dizziness

Severe headache

Stomach cramps

Diarrhea

Nausea

A sharp drop in blood pressure

Loss of consciousness

Treat allergic reactions immediately

If an allergic individual is stung, emergency medical treatment should be sought at once. If the allergic patient has injectable epinephrine such as the EpiPen? or EpiPen? Jr auto-injector at hand, it should also be administered immediately to reverse the potentially deadly symptoms of anaphylaxis. Prompt administration of epinephrine is important because even seemingly mild allergic reactions can escalate to deadly anaphylaxis in minutes.2

Side effects of epinephrine may include palpitations, tachycardia (an abnormally fast heartbeat), sweating, nausea and vomiting, and respiratory difficulty. Cardiac arrhythmias may follow administration of epinephrine. Patients should ask their physician about the circumstances under which this life-saving medication should be used.

Many physicians also recommend that antihistamines such as diphenhydramine be administered to lessen the symptoms of an allergic reaction, but antihistamines should only be taken in addition to epinephrine for the treatment of anaphylaxis and should not be considered a substitute for it. Only epinephrine can halt the potentially deadly effects of anaphylaxis.

Even when epinephrine is used, severely allergic people experiencing anaphylaxis may need emergency respiratory or cardiac care, or even resuscitation if they stop breathing. In any case, when an allergic person is stung, he or she will need professional care to determine whether additional epinephrine, steroids, antihistamines, or other treatments are required. Follow-up diagnosis and care by medical professionals after self-administration of epinephrine for insect stings may be critical to recovery.

Delayed or secondary reactions do occur, and patients should remain under medical supervision for at least 4 hours after an episode of anaphylaxis.3 As many as 25% of people who experience an anaphylactic reaction will have a recurrence up to 48 hours after the initial reaction and will require further medical treatment, including additional epinephrine.4-6 Therefore, it is essential that anyone who experiences anaphylaxis is equipped with enough self-injectable epinephrine to treat additional episodes if necessary, whether they are secondary reactions or result from future exposures to anaphylactic triggers.