Auckland Allergy & Eczema Clinic

Insect Sting Allergy

Insect Sting Allergy

Vincent St Aubyn Crump FRACP - April 8, 2013

Allergies to Stinging Insects

Allergic reactions to insect stings have been known since ancient times. The first recorded death to a wasp sting involved an Egyptian Pharaoh who was stung around 2000BC.

Deaths from stinging insects are rare, with 40 to 50 cases recorded annually in the United States. In Australia, there is a yearly mortality of approximately 1 per 10 million of population. In New Zealand this means 1 death every 3 years. In spite of the small number of recorded fatalities, adverse reactions to bee or wasp stings are relatively common. Between 4 and 8 of every 1000 Americans have experienced a systemic reaction to a sting, and presumably the figure is similar for Australasia. Such reactions may cause considerable anxiety and many victims adopt major and extremely restrictive changes in lifestyle as a result of their fears of subsequent more severe reactions. The objective of management should be to reassure the vast majority of patients that they could return to a normal lifestyle, while identifying the small subgroup that indeed are at risk and offering them appropriate treatment alternatives.

There are two types of reaction to insect bites. One is a local reaction that affects the skin where the bite occurred. The other is a general or anaphylactic reaction, which affects the whole body and may be life threatening. Most people have local reactions.

Local reactions

Local reactions are usually short-lived. There may be discomfort or pain for a few hours and swelling is common. The swelling may occur immediately after the bite or one to two days later. It may be very large sometimes the size of a small grapefruit. It may last for a few days but usually disappears on its own.

How to treat local reactions

The first step in dealing with a local reaction is to decide whether the insect left its stinger in the skin. Honeybees have barbed stingers that stay in the skin and continue to pump more venom. If stung by a bee, you should remove the stinger immediately with tweezers or your fingernails. Try no to squeeze the stinger because that releases more venom into the skin. Other insects of the hymenoptera group such as wasps, yellow jackets and hornets do not leave their stingers behind.

Ice packs followed by calamine lotion may be used to relieve itching and pain. Sometimes oral antihistamines are used to relieve itching. Scratching with dirty hands or fingernails could lead to infection, so avoid scratching.

General (anaphylactic) reactions

General reactions are not common but they can be serious. When they occur within a few seconds to an hour after the bite they are called anaphylactic reactions.

The symptoms of general reactions are:

  • Itchiness and hives over the whole body
  • Nausea, vomiting, diarrhoea
  • Lightheadedness
  • Swelling of the eyelids, lips or tongue
  • Difficulty breathing
  • Rapid heart beat
  • Loss of consciousness or seizures

How to treat a general reaction

If the individual has a general reaction after being stung by an insect, take him or her to the doctor immediately, as a fatal reaction is possible if appropriate treatment is not given.

Once someone has had a general reaction, you should make sure you have medication to use in case of another sting. Available kits, called EpiPen and ANA Kits, contain preloaded adrenaline injection, an antihistamine and a tourniquet. Your doctor will explain how to use them and what dose of the medicine to use. Kits should be kept at home, in the car, at the bach – anywhere a sting is possible.

The patient should also wear a Medic-Alert bracelet to indicate sensitivity to insects.

Prevention of future attacks

The possibility of increasing the individual’s tolerance to insect stings should be discussed with your doctor. This procedure, known as immunotherapy or desensitisation, is done by using insect venom.

Immunotherapy or allergy shots, for bee or wasp stings, are currently recommended when there is a history of general reactions involving breathing difficulty or loss of consciousness. It is not recommended for local reactions resulting from a sting.

The efficacy of immunotherapy using pure bee or wasp venom is well established and protects against further systemic reactions in about 98% of cases. Therefore, all patients with life threatening reactions to insect venom must be offered immunotherapy.

Avoiding Insect Stings

Explain to the child where stinging insects are likely to be:

  • Honeybees live in hives in old trees and are often found in clover.
  • Wasps nest in sheltered places, such as the eaves of buildings, behind shutters, in shrubs and woodpiles.
  • Hornets nest in bushes or high in trees.
  • Yellow Jackets nest under logs or rocks or in the ground and may emerge through a small hole in the ground.

Also be sure that your child is aware of, and obeys, the following rules for dealing safely with stinging insects.

  1. Do not walk barefoot or wear open-toed sandals anywhere. Even hard beach sand can harbour certain types of wasps.
  2. Do not use perfumes, hairsprays, hair tonics or other cosmetics as these may attract insects.
  3. Avoid loose clothing in which insects may become trapped.
  4. Avoid brightly coloured clothing or clothes made from rough materials such as corduroy or denim since these can attract insects.
  5. Avoid keeping food, especially highly sugared food, outside unless it is properly covered.
  6. Avoid outdoor trashcans as these often attract insects.
  7. Do not touch objects outside without first looking to see whether there is an insect on or in them.
  8. Do not idly kick rotting logs or bushes that are unfamiliar to you.
  9. Do any gardening cautiously to avoid striking a hidden nest.
  10. If a bee lands on you, do not slap it. Instead, gently blow it away.
  11. Try using insect repellants (unfortunately, these are often of little use).

As a parent you can help by:

  • Keeping the area around garbage cans clear and occasionally spraying the area with insecticide.
  • If a bee or wasp hitches a ride in your car, open all windows and it will leave. Panic may cause an accident.
  • Have nests and hives around your home removed by a professional exterminator or by someone who is not insect sensitive.