Immunization with insect venom can also prevent most allergi

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Beware the Stinging Bee on the Fourth Weekend
   
  By Michael Smith, MedPage Today Staff Writer
July 01, 2005
 
 
WASHINGTON, July 1-A bee only weighs a fraction of an ounce, but it can spoil your whole holiday weekend.


While it would take about 300 insects to weigh an ounce, the cocktail of proteins that a bee's stinger can inject is often enough to cause symptoms ranging from hives to fatal shock in people allergic to the venom.


And the same applies to other stinging insects, such as yellow jackets, hornets and wasps, according to the Asthma and Allergy Foundation of America here. There's another wrinkle in many parts of the U.S. -- the fire ant, which bites and also stings, can also cause allergic reactions.


Most of those reactions are mild -- hives or itching -- but some are more serious and in the worst cases, death can follow quickly. Every year, 100 people in the U.S. die from insect stings.


"It's important to know if you're allergic, because then you can take precautions," said the foundation's Angel Waldron. Those precautions include wearing dark clothing (insects are attracted to bright things), avoiding perfumes (they're also attracted by scent), wearing shoes (so you don't step on an insect in bare feet), and not leaving food and trash out in the open.


Immunization with insect venom can also prevent most allergic reactions, said immunologist David Golden, M.D., an associate professor at the Johns Hopkins University School of Medicine in Baltimore.


Immunologists at Johns Hopkins were among the pioneers in the use of insect venom in immunotherapy 30 years ago -- a therapy that, he said, has been shown to be safe and almost completely effective in preventing dangerous reactions.


Dr. Golden and colleagues recently re-studied more than 500 people -- some immunized and some not -- 15 years after a study of immunizing children with insect venom.


The bottom line of the new study, published in the New England Journal of Medicine last year, is that venom immunotherapy lasts for years, he said. Among those who were treated -- even 15 years after the therapy -- the risk of an allergic reaction to a sting was less than 5%, he added.


Despite that, he said, the therapy is not widely used.


"We're amazed to this day how many doctors, let alone the public, don't know that venom immunotherapy is available and that it's so effective, or that it is basically the same as any other type of allergy shot," he said.


Part of the problem is that many people dismiss an allergic reaction as "a fluke" and don't even tell their doctors. "We try to get people to understand that if you had a reaction where you were dizzy or had trouble breathing, it can happen again, it probably will happen again, and it can be prevented," he said.


There's really no telling what the reaction to a sting is going to be, he added. Someone could be stung regularly for years with no effect -- other than sudden sharp pains -- and then have an allergic reaction the next time. Or someone could have an allergic reaction several times and then not respond to the next sting.


The only thing that's nearly certain is that the first sting is a freebie -- it's highly unlikely that the body's immune system would be already sensitive to the proteins in insect venom. Dr. Golden said that when people have a reaction to what they think is their first sting, subsequent investigation usually reveals a previous sting, often so early in childhood they don't remember it.


"If they've truly never been stung, there should be no way the first sting could cause a dangerous reaction," he said. "The second one could or the 102nd one could -- that's unpredictable."


The level of the allergic reaction also varies. Some people have local reactions -- a swollen arm, for example -- that are uncomfortable but not dangerous. The system-wide reactions, often characterized by such things as difficulty breathing or dizziness, are the most dangerous.


Many children have what he called "external reactions" -- hives or swelling of the face -- and they tend to outgrow their allergy. But the latest study also showed children with internal reactions, such as swelling of the throat, "did not outgrow it as readily," he said.


"Ten to twenty years later, they still had some 30 per cent chance of a severe reaction."


The implication is that people who have ever had such a reaction should remain concerned, he said.


If you've previously had an allergic reaction to a sting, Waldron said, you should carry a device called an EpiPen, essentially a single-use hypodermic needle that delivers a jolt of epinephrine (otherwise known as adrenalin) that will temporarily counteract the allergic reaction and give you time to get to an emergency ward.


The foundation urges parents to have their children tested for allergies; most adults, Waldron said, know if they've been stung and if they have ever had an allergic reaction to a sting, but they may not know if their kids have been stung.