Take the Sting Out of Summer

Throughout the country, flying and crawling insects are preparing for a summertime assault.

"Unfortunately, pollens aren't the only allergens in the air this time of year," says Dan Atkins, MD, a pediatric allergist at National Jewish Medical and Research Center. "Another bunch of allergens are flying around inside special injection devices that, when encountered, may threaten the life of those who are sensitive. These potential allergens are found in the venom injected by stinging insects."

Picnickers all over the country have to contend with stings by yellow jackets, yellow hornets, white-faced hornets, wasps and honeybees. These stings can cause allergic reactions ranging from minor irritants, to serious medical problems.

More than 1 million Americans report allergic reactions to insect stings; about 50 people each year die from the stings.

Insect sting reactions fall into two categories: immediate and delayed. Immediate reactions occur within four hours of a sting. A normal reaction consists of localized pain, swelling and skin redness, lasting for several hours, at the sting site.

Another type of immediate reaction is called a "large local reaction" because it consists of a large area of swelling surrounding the sting site. "A large local reaction can be accompanied by low grade fever, mild nausea, malaise and fatigue," Dr. Atkins says.

Treatment of local reactions in people without a history of insect sting sensitivity include aspirin for pain and ice to reduce swelling. For those with a history of large local reactions, taking an oral antihistamine (preferably nonsedating) is recommended.

"A third type of immediate reaction is the most dreaded: anaphylaxis. These reactions involve multiple organ systems simultaneously and most often begin within minutes of the sting although they can occasionally begin an hour or so later."

Common signs and symptoms of anaphylaxis are flushing, itching, hives, swelling, sneezing, runny nose, swelling of the throat, breathing difficulties, nausea, abdominal cramping, vomiting and diarrhea. In severe episodes of anaphylaxis, an irregular heartbeat and shock can occur.

People who have had severe or anaphylactic reactions in the past should wear a bracelet identifying their insect sting sensitivity, be taught to self-administer injectable epinephrine, and be reminded to keep epinephrine and antihistamines available at all times. After epinephrine and antihistamines are taken following a sting, call 911.

Delayed reactions occur more than four hours after a sting. There have been isolated reports of serum sickness-like syndromes occurring about a week after a sting with hives, fever, malaise and joint pain. These patients are at risk for anaphylaxis with subsequent stings and are candidates for venom immunotherapy - shots for allergies to insect venom.

Venom immunotherapy is highly effective in preventing subsequent sting reactions. "After reaching maintenance doses of immunotherapy, 95 percent of venom-treated patients are able to tolerate single stings," Dr. Atkins says. "And sting reactions that do occur are generally milder."

He recommends that patients with a history of moderate to severe episodes of anaphylaxis following an insect sting be referred to an allergist. Adult patients who have a positive venom skin test generally are considered candidates for specific-venom immunotherapy. Children with skin symptoms alone have only a 10 percent risk of systemic reactions and aren't considered candidates for skin testing or immunotherapy.