Each year millions of Americans are stung by bees, wasps, hornets, yellow jackets, and fire ants. These insects, members of the Hymenoptera family, inject venom into their victims when they sting. For a small percentage of people allergic to these venom's, such stings may be life-threatening. The usual reaction to a sting lasts only a few hours. Redness and swelling may develop at the site of the sting. Localized pain and itching is also common. These symptoms resolve rapidly. Occasionally such reactions are larger and more symptomatic, a condition termed a large local reaction. This type of reaction may persist for several days but is not an allergic reaction.
Allergic reactions to insect stings can involve many organ systems of the body, in addition to the skin, and develop rapidly after the insect strikes. Symptoms may include nausea, dizziness, stomach cramps, and diarrhea as well as the more common symptoms of allergy: itching and hives over large areas of the body, wheezing, and difficulty in breathing. In severe cases, a sharp fall in blood pressure may result in shock and loss of consciousness. The medical term for such a serious reaction is anaphylaxis. Anaphylactic reactions may be fatal if prompt emergency medical treatment is not obtained.
There are several ways to prevent and treat such reactions in persons allergic to one or more insects of the Hymenoptera family. Common sense prevents many stings. Hymen-optera-sensitive patients should take measures to avoid being stung. Calm, quiet behavior without sudden movement or waving of the arms when in the presence of these insects often prevents trouble. Other precautions include:
Prevention at home
The smell of food attracts most of these insects. Be careful when cooking, eating, or even feeding pets outdoors. Keep food covered until eaten. Insects are attracted to trash containers and fruit trees with fallen fruit. Keep trash areas clean and trash covered. Use insecticide sprays to keep insects away.
Personal Methods of Prevention
Gardeners should take additional precautions. Accidentally disturbing a hive will irritate the insects, inciting them to swarm. Watch for nests in trees, vines, shrubs, wood piles, under the eaves of the home, and in other protected places. Use hedge clippers, power mowers, and tractors with caution.
Sweet odors attract insects. Persons allergic to these insects should avoid the use of perfume, scented hair spray and other hair applications, scented suntan lotion, and other cosmetics. Because bees gather nectar from clover and other ground plants, don't go barefoot; wear closed-toe shoes outdoors. Avoid loose-fitting garments that can trap insects between material and skin. Bright colors, flowery prints, and black clothing also attract stinging insects more than do light and muted colors like white, tan, khaki, and green. Hymenoptera sensitive persons should keep an insecticide aerosol in the glove compartment of their car in the event that a stinging insect becomes trapped inside while the care is in motion.
Immediate Removal of the Stinger
Insect allergic persons should not participate in outdoor activities alone. These activities include hiking, boating, swimming, and golfing. When a sting occurs the insect-allergic patient may require assistance in receiving prompt emergency treatment.
Removal of the stinger from the skin immediately after the sting may prevent some of the harmful effects of the venom. Among Hymenoptera species, only the honey bee leaves her stinger (with venom sac attached) in the skin of its victim. Since it takes several minutes for the venom sac to inject all of the venom, instantaneous removal of the stinger and sac will limit the amount of venom received. A quick scrape of the fingernail removes the stinger and sac. Avoid squeezing the sac since this forces more venom through the stinger and into the skin.
Nests, Colonies, and Hives
Hornets, wasps, yellow jackets, and fire ants don't leave their stingers. They should be brushed from the victim's skin promptly with deliberate movements to prevent additional stings. The victim should quietly and immediately leave the area.
Since all Hymenoptera insects will sting if their home is disturbed, it's important to destroy hives and nests around your home. The insect-allergic person should not perform or watch this potentially dangerous activity. A trained exterminator or another person skilled in hive removal should be employed.
To kill insects, use a commercially available stinging-insect aerosol in the evening when most of the insects have returned to the nest. Use appropriate precautions. Wear a hat, long-sleeved shirt, and thick work gloves. Tuck pant legs into socks or boots.
Burning or flooding of nests should be avoided. This will not usually kill all of the insects and will irritate the survivors. Inspect the home and yard weekly, especially in spring and summer, to detect new hives or nests.
Wasps build open-comb nests or mud structures under eaves, in carports, behind shutters, in shrubs and in woodpiles. Yellow jackets usually nest underground in abandoned burrows or tunnels of small rodents, between cracks of rock walls, or between the walls of frame buildings.
Hornets build gray football-shaped hives usually in shrubs or trees, often high up or far out on a branch. Honey bees may be found in commercial hives but may also swarm onto twigs or branches. Their hives may be found in the hollow trunks of trees, suspended from branches, or even between the outside walls of buildings. Ants usually build their colonies in the ground, particularly in areas less frequently disturbed by man.
Any person who has had a serious adverse reaction to an insect sting should be evaluated by an allergist. The allergist may recommend testing and, if appropriate, treatment and avoidance measures.
Additional Treatment Measures
Approximately two million Americans are severely allergic to the venom of stinging insects. Severe allergy occurs when the victim's immune system produces too much of a special type of antibody, called IgE, against the injected venom. Why only some people produce excessive amounts of IgE antibody remains unknown.
The production of this antibody follows an initial sting, but there usually is no severe allergic reaction to that encounter. When the person is restung by another insect of the same or similar species of bee, hornet, or ant, the venom enters the body where it combines with the IgE antibody already present in response to the earlier sting. The combination of venom antigen and IgE antibody triggers internal reactions resulting in severe allergic symptoms. Skin or blood (RAST) testing for insect allergy is used to detect the presence of significant amounts of these IgE antibodies in the patient.
Persons severely allergic to the venom of stinging insects can now be treated with venom immunotherapy. For many years these people could only be immunized with extracts prepared by grinding up the entire bodies of insects to which they were sensitive. These whole body extracts were presumed to contain the venom of the specific insect. Further research determined that these preparations did not contain enough pure insect venom to be consistently effective for immunization.
A better way to collect pure venom is now available. Armed with these preparations, allergists use immunotherapy to administer gradually stronger doses of venom stimulating the patient's immune system to become more and more resistant to future insect stings. Once the patient is receiving the highest dose of venom, protection against future severe reactions will be present.
Insect venom's are available for the treatment of allergies to honey bee, yellow jacket, hornet and wasp. Whole body extracts are still used for fire ant hypersensitivity since pure ant venoms are not yet available.
Depending on the severity of your allergy, your allergist may instruct you in the use of an epinephrine kit. This self-treatment kit is used in cases of severe allergic reactions. The pre-filled syringe in the kit is filled with epinephrine. This medication aborts or reduces the allergic reaction.