Bee Sting

Bee Sting Allergy

Stinging insects, such as honeybees, can cause severe allergic reactions by injecting venom into the skin of a person who is allergic to proteins contained within the venom.

Bee Sting

Allergic reactions to flying stinging insects (honeybees, hornets, wasps and yellow jackets) are relatively common.

Most people who are stung by these insects will develop a reaction at the site of the sting that will cause pain, swelling, redness and itching. A smaller percent of people -- about 10 to 15% -- also will experience larger areas of swelling, and the swelling can last up to a week.

Rarer still are people who have full-blown allergic reactions that cause anaphylaxis. About .5% of children and 3% of adults will experience anaphylaxis after a stinging insect bite.

In addition, about 40 people in the United States die every year from a venom allergy, although there are likely other deaths from insect stings that are attributed to other causes, and therefore this number is probably a low estimate. Most of these deaths occurred among people without a known history of venom allergy. Still, keep in mind this is a very small number of people.

Who's most at risk of having an allergic reaction? People with a history of other allergic diseases, such as allergic rhinitis and asthma.

Signs of Anaphylaxis

When someone has whole-body (systemic, or anaphylaxis) allergic reactions to insect stings, they may experience any or all of the following symptoms, usually within a matter of minutes to a few hours:

  • itching all over,
  • hives or swelling that spreads from the site of the sting,
  • flushing,
  • runny nose, sneezing or post-nasal drip,
  • itchy/watery eyes,
  • swelling of the lips, tongue or throat,
  • shortness of breath, wheezing or coughing,
  • stomach cramping, nausea, vomiting or diarrhea,
  • lightheadedness, fast heart rate, low blood pressure or passing out,
  • sense of panic or metallic taste in the mouth.

Which Stinging Insects Cause Venom Allergies?

Yellow jackets are wasp-like insects that live in mounds built into the ground, They tend to be aggressive insects, and are a common nuisance at picnics and around trash cans where food and sugary drinks are abundant. Stings on the lip or inside the mouth or throat can occur when a drink is taken from an open can of soda that a yellow jacket had crawled into. Occasionally, stings from yellow jackets can result in a skin infection because these insects can carry bacteria.

Hornets, including yellow and white-faced hornets, build paper-mâché type nests in trees and shrubs. These insects may be very aggressive, and sting people because of a mild disruption, such as someone nearby mowing a lawn or trimming a tree.

Wasps build honeycomb nests under the eaves of a house, or in a tree, shrub or under patio furniture. They tend to be less aggressive than yellow jackets and hornets, and mostly feed on insects and flower nectar.

Honeybees commonly nest in tree hollows, logs or inside buildings. Away from their hive, honeybees tend to be non-aggressive, but can be more aggressive when their hive is threatened or disturbed. Stings from honeybees are common when a person walks barefoot on a clover-filled lawn. They are the only stinging insect to routinely leave a stinger in the victim’s skin, although other stinging insects occasionally do so as well.

Africanized (killer) honeybees are far more aggressive than domestic honeybees, which were created by cross-breeding African honeybees with domestic honeybees in South America for the purpose of greater honey production. Their venom is essentially the same as domestic honeybees – meaning that a person allergic to a typical honeybee will also be allergic to Africanized honeybees. They tend to sting in large groups, sometimes by the hundreds.

Bumblebees rarely sting people because they are non-aggressive and typically mild-mannered. They will sting if provoked or if their nest is disturbed, but they are so loud and slow, a person usually has plenty of time and warning to escape. They nest in the ground or in piles of grass clippings or wood and feed on insects and flower nectar.

How Do I Avoid Being Stung?

Put simply, the best way to prevent an allergic reaction is to avoid being stung. Here are a few tips:

  • Hire a trained exterminator to treat any known nests in the immediate area; periodic surveillance for further infestation should be performed.
  • Avoid looking or smelling like a flower. Do not wear brightly colored clothing or flowery prints, or perfumes or other scents that will attract insects.
  • Always wear shoes when walking outside, particularly on grass.
  • Wear pants, long-sleeved shirts, gloves, close-toed shoes, and socks when working outdoors.
  • Use caution when working around bushes, shrubs, trees and trash cans.
  • Always check food and drinks (especially open cans of soda or drinks with straws) before consuming, especially at pools and picnics, where yellow jackets are known to be present.
  • Keep an insecticide, approved for the use on stinging insects, available should treatment of a nest be necessary.

Bee Sting Allergy

Testing is performed using allergy skin testing or by performing a RAST. Skin testing is still the preferred method and the procedure is similar to testing for pollen or pet allergies. However, it may be necessary to use increasing concentrations of venom extracts to make a diagnosis. Allergists usually test for all stinging insects (bees, wasps, etc.) since studies have shown that people usually can't identify which type of insect stung them.

A person stung by only one insect may show positive allergy tests to more than one type of insect. In this situation, treatment using venom from all of the species is usually given.

Who Should be Tested for Venom Allergy?

It's not always a clear-cut case, but in general:

Testing is not needed If a person has never been stung by an insect, or never had any symptoms (other than pain at the site of the sting) as a result of a sting, there is no need to perform any venom allergy testing.

Or, if a child under 16 years of age has only skin symptoms (such as hives and swelling) after a sting. This is because anaphylaxis will only occur in up to 10% of future insect stings.

Or, if a child or adult has a large local reaction, where swelling occurs at the site of the sting only, is not usually a reason to perform venom testing or to administer venom allergy shots. This is because the chance of developing anaphylaxis with future stings is only about 5 to 10% for both children and adults.

(A few studies show that these reactions can be decreased with the use of venom immunotherapy, and this may be required in situations where stings are frequent and the swelling disrupts a person’s quality of life or ability to work.)

Testing is needed: If a person of any age has symptoms of anaphylaxis (see page 1) after being stung.

That's because the person has about a 60-70% chance that future insect stings will cause a similar reaction. The chance of a reaction with a future sting will decrease over time but still remains at about 20% many years after the last sting.

Also, if there is particular parental concern or the child is at high risk for frequent stings, venom testing and treatment is a reasonable option. People older than 16 with these same concerns should have venom testing and treatment, given a higher risk of anaphylaxis with future stings.

Of note: If a person is found to have a positive allergy test to venom, yet has had no symptoms with stings, the chance of developing anaphylaxis with future stings is approximately 17%. As an allergist, I encounter these situations in my clinic on occasion, such as when a non-allergy physician orders a RAST test to venoms for a person who is concerned with a bee-sting allergy but without a history of a reaction. In this circumstance, because a positive test now exists, venom allergy shots need to be offered given the small (but significant) chance of a severe allergic reaction in the future.

Bee Sting Allergy Treatment

The treatment of venom allergy involves the management of an acute reaction, as well as the prevention of future reactions.

Immediate treatment of acute reactions. Epinephrine is the treatment of choice for anaphylaxis. People with venom allergy are encouraged to carry a self-injectable form of epinephrine, such as an Epi-Pen or Twin-Ject device. If this medication is required, immediate medical attention is also needed, and the person should call 911 or go to the emergency room.

 

If itching or hives is the only symptom, an oral antihistamine may be all that is required although seeking emergency medical attention is still advised. If symptoms worsen or swelling of the skin affects the ability to breathe, then epinephrine will be required.

If a stinger remains in the skin, such as with a honeybee sting, it should be removed quickly so that more venom is not injected into the sting. Do not squeeze the stinger or the site of the skin -- instead, pull the stinger out with tweezers or scrape the stinger out with the edge of a credit card. Put ice or a cold compress at the sting site to reduce local swelling.

Treatment of future reactions. To prevent reactions to future insect stings, avoid being around stinging insects. If a person has experienced anaphylaxis, or whole-body skin symptoms (hives, itching, flushing, swelling away from the sting site) in those 16 years and older, then venom and testing is required.

Immunotherapy, or allergy shots, using purified venom from the type of insect to which a person is allergic, can cure venom allergy. Allergy shots using pure venom is given in much the same way as allergy shots for pollen allergy. After a person is receiving appropriate doses of venom allergy shots, the chance of a reaction with future stings is reduced to less than 5%.

After a series of venom allergy shots for at least 3 to 5 years, most people can stop the shots without a significant increase in the chance of allergic reactions.

However, some people with severe, life-threatening reactions from insect stings, or those who have had anaphylaxis from the venom allergy shots themselves, may require life-long venom allergy shots. This is because a person’s chances of a reaction with future stings may slowly increase to as high as 20% many years after venom allergy shots are stopped. This topic is an evolving area of venom allergy research and requires careful discussion between a person and their allergist.

Some allergists perform venom allergy testing, either with skin testing or RAST, after venom immunotherapy has been given for a period of time. Venom immunotherapy can be stopped in the majority of people whose allergy test turns negative, although the test does not always turn negative, even in people who have received venom allergy shots for years.

All people with a history of allergic reactions to insect stings, including children with skin-only reactions and even those with large local reactions, should consider wearing a Medic-Alert bracelet identifying their medical condition, as well as having an injectable form of epinephrine available for immediate use.

Sources:

  • Moffett JE, Golden DBK, Reisman RE, et al. Sting Insect Hypersensitivity: A Practice Parameter Update. J Allergy Clin Immunol. 2004;114:869-886.
  • Golden DBK. Insect Sting Allergy and Venom Immunotherapy: A Model and a Mystery. J Allergy Clin Immunol. 2005;115:439-47.
  • The American Academy of Allergy, Asthma and Immunology. Accessed June 24, 2007.

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