The Hidden Sting of Bee Stings
Negative skin tests don't guarantee you're allergy-free
WEDNESDAY, July 25, 2001 (HealthDayNews) -- Think you're safe from a bad reaction to a bee sting?
Don't be too sure, new research suggests.
Even people who've had their skin tested for a bee-sting allergy and have come up negative still could face life-threatening consequences should a yellow jacket decide to make them its target.
"Our tests are not 100 percent accurate, so sometimes we don't find it and they really do have the allergy," says Dr. David Golden, who recently investigated the accuracy of testing methods for this particular allergy.
"[That] leaves them potentially at risk," Golden, an associate professor of medicine at Johns Hopkins School of Medicine, says. "They can get stung, and have a bad reaction."
Allergists most often expose someone's skin to bee venom to check whether that person is allergic. It's "usually correct, but it turns out that it's not a guarantee," he says.
Skin tests are "about 95 percent accurate, but it's the 5 percent that we're worried about," Golden says.
Most people who get stung will suffer varying amounts of pain, redness and swelling around the area of the sting, generally lasting a day or two. But an estimated 4 percent of all Americans face more severe reactions because they're allergic to stinging insects, ranging from bees, wasps and hornets to fire ants, according to the American Academy of Allergy, Asthma and Immunology.
For them, a sting can lead to breathing problems, itching and swelling far from the site of the sting, dizziness, loss of consciousness and even death.
Because of the potential risk, people who know they're allergic often carry a pen-like container of epinephrine so they can inject themselves with the adrenaline-like antidote should they get stung.
But sometimes people think they've outgrown the allergy, and complacency sets in. And that can spell trouble, Golden warns.
"If the [skin] test is negative, the allergist should still tell the patient there's a small chance of reaction," he says.
Taking it a step further, he suggests that allergists do blood tests as well.
"The skin test is more sensitive, but the blood test is more specific," he says. "Traditionally, we thought if the skin test is negative, there's no point in doing the blood test." But now he advises something different.
"If the skin test is negative do the blood test," Golden says. "If the blood test is still negative go back and do the skin test again. If it's still negative, we can be pretty sure [the tests] are accurate."
Allergists need to "make double-sure and triple-sure that we're as sure as we can be," he says.
When Golden and his colleagues at Johns Hopkins' Allergy and Asthma Center in Baltimore tested 307 people who'd had previous allergic reactions to bee stings, 99 of them -- or 32 percent -- tested negative on skin tests. Of that group, 56 people also got negative results from subsequent blood tests, the study says.
And, of the 51 participants with negative skin tests who agreed to be stung by a live bee, 11 had allergic reactions. Details of the study appear in a recent issue of the Journal of Allergy and Clinical Immunology.
Dr. Mary Beth Bollinger, director of allergies at the University of Maryland Hospital for Children, agrees with Golden's advice.
"You always have to err on the side of caution," she says.
"Once you get a severe allergic reaction, not everybody is going to have the same allergic reaction with a subsequent sting," Bollinger says. "But there's at least a 50 percent chance they'll have another life-threatening reaction."
The odds improve, however, with allergy shots.
"They'll have 85 to 90 percent protection with those allergy shots, and that's pretty good odds," she adds.
Until a more sure-fire test is developed -- something Golden says doctors at Johns Hopkins and elsewhere are working on -- retesting should be the watchword.
"A lot of people are walking around with the allergy in their systems, even if they have no symptoms," Golden says. "There are twice as many people who have the allergy in their systems as have had a reaction."
What To Do
If you've been stung, tell your doctor about any reaction, say both Golden and Bollinger.
If you've had a severe reaction, make sure you have epinephrine and you know how to use it. Primary-care doctors can prescribe the pen-like device, and either a doctor or a pharmacist can show you how it works, Bollinger says. Carry it with you wherever you might encounter stinging insects, such as on a hike or at a picnic.
For more information on allergy testing, visit the Mayo Clinic.