Insect venom allergy

Everyone gets stung or bitten by an insect occasionally, but it usually just causes a bit of itching, redness and a slight swelling. But in people with an insect venom allergy, a sting/bite can cause severe reactions that can occasionally be life-threatening. This is because the immune system fights against certain protein elements in the venom.

With an insect venom allergy, the area around the sting or bite swells up badly. The swelling often has a diameter of over 10 centimeters and lasts more than 24 hours. It often causes bad pain, and itching or burning.

People with an allergy face particular danger if stung/bitten in the mouth or throat. The swelling can narrow the airways and make breathing difficult. However, it is rare that the swelling is so bad that there is a risk of suffocation.

Milder reactions include:

• wealing (urticaria)
• itching over the entire body
• dizziness
• nausea 
• stomach complaints
• difficulty in swallowing
• general weakness
• swellings to the face or hands

A severe reaction can include:

• shortness of breath
• drop in blood pressure
• loss of consciousness
• cardiac arrest

In most cases the symptoms appear immediately after the sting/bite, but occasionally hours afterwards.

The entire body can also show symptoms. This is an anaphylactic reaction that can range from mild to life-threatening. An anaphylactic reaction may also possibly fade away initially, before returning within 8 hours.

For more information on anaphylactic reactions, go to the website gesundheitsinformation.de.

The most common trigger of allergic reactions is the venom from bees or wasps. It can be helpful to understand bee and wasp behaviors in order to be able to avoid them, and to respond correctly if stung or bitten. Bee stings tend to cause more severe reactions than wasp stings.

Much rarer are reactions to hornet venom (usually when the person has a wasp sting allergy) or bumblebee venom (usually when the person has a bee sting allergy). In Germany there are hardly ever allergic reactions to midge, horse fly or ant venom, except at the site of the bite itself.

For diagnostic purposes it can be important to know which insect did the stinging/biting:

Bees

• fly from spring to late summer.
• tend to be pacific, as long as they do not feel threatened.
• lose their sting after using it; it usually remains embedded in the person’s skin.
• are usually found near beehives and blooms.

Wasps

• fly from summer to late fall.
• get aggressive more quickly – they feel threatened more easily if a person moves or blows them away.
• keep their sting after using it.
• are often found near food and trash.

Around 2 percent of the population react to insect stings/bites with discomfort in areas other than where stung or bitten.

People who, in general, get stung/bitten more often than other people also tend to be affected more often. Beekeepers and their relatives, and people who sell baked goods or fruit or work in agriculture are at greater risk.

Allergic reactions to insect stings or bites do not usually cause lasting harm.

Around 20 fatalities per year from allergic reactions to bee, wasp and hornet stings are reported in Germany. The real figure is likely to be slightly higher, as allergic reactions are not always entirely evident as the cause of death.

The main thing is to avoid insect stings and bites. The following behaviors help:

• Avoid going near to trash, beehives and wasps’ nests.
• Do not hit at wasps and bees – they sting to defend themselves.
• Do not eat outdoors when there are lots of insects in the air.
• If you are eating outdoors, remain alert and clear away the table immediately afterwards.
• Cover drinks glasses and use drinking straws.
• Clean mouth and hands after eating.
• Behave with calm, and move slowly.
• Protect skin with clothing.
• Close windows during the day.

First, the doctor asks the patient the exact details of their complaint. As wasp and bee stings cannot always be clearly differentiated, the place where the insect sting/bite occurred is important, as is the insect’s behavior. Sufferers often mix up bees and wasps, so it is not always clear which insect did the stinging/biting.

If reactions occur more widely than at the place stung or bitten, skin and blood tests will be carried out. They are examined to see whether the immune system is reacting sensitively to particular triggers.

In the skin test, a solution with insect venom is applied to the skin. The location is gently scratched and observed to see whether any reddening or itchy wealing occurs. The blood test can identify whether the body has produced antibodies against the insect venom.

If a person has an insect venom allergy, provocation tests can cause severe reactions, so they are not used very often. In a provocation test, which is certainly a good idea with other allergies, larger doses of the likely irritant are gradually applied to the body and the reactions are observed.

The treatment depends on the type of complaints and on whether the person affected has been hyposensitized.

The patient first takes an antihistamine tablet and also, depending on the severity of the skin reaction, a cortisone product.

If there are more severe symptoms such as breathlessness, nausea, circulatory problems or swellings in the mouth and throat, adrenaline should be injected as quickly as possible.

In this case, hyposensitization (a specific immunotherapy) can be advisable. This usually ensures that the reaction to an insect sting or bite is far weaker or does not occur at all.

If it is confirmed that someone has an insect venom allergy, it is important for them to get an allergy passport issued and have it with them at all times.

There is more detailed information, for example about short-term and long-term treatment of an insect venom allergy, at gesunheitsinformation.de.

There is also more information about insect venom allergies at allergieinformationsdienst.de.