Little Insects, Big Allergic Reactions

June 16, 2011 -- Insect stings are little more than painful nuisances for most people. But for others, the venom from insects can cause severe allergic reactions and even death. That’s according to a joint task force of the American College of Allergy, Asthma and Immunology, the American Academy of Allergy, Asthma & Immunology, and the Joint Council of Allergy, Asthma and Immunology, which has updated practice guidelinesfor diagnosing and treating stinging insect allergies.

Serious allergic reactions to insect stings cause at least 40 deaths each year in the U.S. Experts estimate that life-threatening reactions to insect stings occur in 3% of adults and up to 0.8% of children.

Richard Nicklas, MD, a clinical professor of medicine at George Washington Medical Center in Washington, D.C., and one of the authors of the guidelines, says that for most people insect stings usually cause temporary pain, swelling, and redness, symptoms that can be treated at home.

Some Stings May Require Immediate Medical Attention

“An allergic reaction is more severe and often includes hives, itching, and swelling in areas other than the sting site,” Nicklas says in a news release. “These reactions require immediate medical attention.”

Symptoms of a serious life-threatening allergic reaction, also called anaphylaxis, can include tightness of the chest, difficulty breathing, hives, swelling of the tongue, throat, nose, and lips; nausea, cramps, diarrhea, headache, dizziness, or loss of consciousness. The updated guidelines say research indicates that allergy shots, also known as immunotherapy, could prevent many adverse reactions. With allergy shots, people could build up their immune system’s tolerance to insect venom.

The task force also says some insects considered fairly harmless may be dangerous, such as bumblebees.

The practice guidelines say people who feel they are at increased risk of serious reactions should see an allergist for evaluation and possible treatment. People at highest risk include those who have asthma or a history of severe reactions to insect stings, and people with heart disease, high blood pressure, or people taking certain medications for those conditions may require special attention.

The statement says people who have a history of serious adverse reactions to insect stings should:

• Educate themselves about bees and other stinging insects so that they can avoid them.
• Carry epinephrine at all times for emergency self-treatment and receive instructions on how to properly use the medication. Consider a prescription for an additional injector because some people with anaphylaxis may need more than one epinephrine injection.
• Undergo testing for specific antibodies to stinging insects.
• Be considered for immunotherapy (allergy shots)  if test results for the antibodies are positive.

Consider carrying medical identification (like a bracelet or pendant) stating their insect sting allergy.

Know Where Bees Live

The practice guidelines also advise that people be aware of where stinging insects might be found to avoid getting stung.

For example, yellow jackets tend to build nests in the ground and can be stirred into attack. Hornets, which are highly aggressive, build large nests, usually in trees, the statement says, and wasp nests generally are found in shrubs and under eaves of houses or barns. Domestic honeybees are found in commercial hives, but their wild cousins live in tree hollows or old logs.

The statement notes that Africanized honeybees are hybrids, descendants of domestic honeybees and African honeybees in South America, and are much more aggressive, so much so that they often attack in swarms.

Fire ants can also produce painful stings and dangerous reactions.

The identification of the stinging insect can be useful to people and doctors in diagnosing and treatment, as well as for educating patients in avoidance.

Other tips noted to help people avoid stings include keeping food covered when eating outdoors and avoiding drinking beverages from cans or straws when outdoors. That’s because stinging insects are attracted to sweet liquids and may crawl inside the can or straw. Also, people should keep outdoor garbage cans covered with tight-fitting lids.