Wasp on sweets - Wasp venom allergy - aha! Swiss Allergy Centre - Info on allergies - © Image: Ingo Bartussek / fotolia

Insect venom allergies are mainly triggered by bee and wasp stings. Stings in the mouth and throat area can even cause life-threatening swelling for non-allergic people. Annually there are three or four fatalities across Switzerland. Wasp venom allergy is not hereditary.

Contents overview:
Causes and triggers of wasp venom allergy
Symptoms of wasp venom allergy
Diagnosis and differential diagnosis
Therapy and treatment
Tips and tricks
Facts and figures
A serious allergic reaction – act correctly in an emergency
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Causes and triggers of wasp venom allergy

Wasp stings mainly happen in late summer and autumn. Unlike bees, wasps retain their stinger after stinging, which means they can sting several times. Hornets are larger and belong to the same family as wasps.

Symptoms of wasp venom allergy

The symptoms of an allergic reaction to a wasp sting appear within minutes but not later than one hour after the sting. The symptoms can be many and varied: from local swelling to itching, urticaria, vomiting through to shortness of breath, palpitations, a drop in blood pressure, loss of consciousness, respiratory arrest and cardiovascular collapse (anaphylaxis).

Diagnosis and differential diagnosis

The diagnosis is based on thorough history-taking with the aid of skin and blood tests. Specific IgE antibodies to Hymenoptera toxins can be identified in the blood by various tests. However, these should be done no earlier than three weeks after the sting.
The same symptoms as with an insect sting can also occur with a food allergy.

Therapy and treatment

People who have already had an allergic reaction to a wasp sting should be told about the risk from being stung again. They are given an emergency kit containing antihistamines, cortisone and possibly an adrenaline prefilled syringe, e.g. EpiPen (handling and shelf life should be checked regularly). Whenever a sufferer is stung, he should take the prescribed medication immediately, even before an allergic reaction develops. If necessary, the adrenaline syringe should also be used.

Desensitisation/specific immunotherapy (SIT) with wasp venom is the only effective causal therapy. The treatment lasts 3–5 years and provides complete protection in 95% of patients.

Tips and tricks

To avoid wasp stings, observe the following rules:

  • A wasp is rarely alone. Avoid the proximity of wasps’ nests (on the ground, in rotten tree branches and hollow tree trunks, in roller shutter casings or in attics).
  • As wasps nest on the ground, do not walk barefoot in meadows and at the edges of woodland.
  • Do not make any hasty movements in the vicinity of wasps.
  • Be cautious when picnicking and eating outdoors, do not leave any left-over food uncovered.
  • Beer attracts wasps, never drink straight out of cans or bottles.
  • Do not use any strongly perfumed hairsprays, shampoos or sun creams.
  • Set up insect screens, especially in bedrooms.
  • Only ride a motorcycle with your helmet closed and wear gloves.
  • If you have wasps’ nests in the immediate vicinity of your home or place of work: notify the police, fire service or local council.

Essential advice for sufferers from wasp venom allergy: always carry your emergency kit.

Facts and figures

In Switzerland 3.5 % of the population suffer from an insect venom allergy.

Editors: aha! Swiss Allergy Centre in co-operation with the Scientific Advisory Board. For prevalence figures, see source references.

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