Insect venom allergy

Dr. med. Mira Seidel is a freelance writer for the medical team.

More about the experts All content is checked by medical journalists.

In the case of an insect venom allergy, the immune system is overly sensitive to certain components of the insect venom. You may develop severe allergic symptoms such as swelling of the face and neck, dizziness, nausea, or shortness of breath. It becomes life-threatening if the allergy causes cardiovascular arrest - those affected need rapid medical help! Read here why an insect venom allergy occurs, how it manifests itself and what can be done about it.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. You can find e.g.in doctor's letters or on certificates of incapacity for work. T63

Insect venom allergy: description

Insect bites are never pleasant. While mosquito bites usually only itch and redden, stings from bees and wasps usually hurt and the affected part of the body swells. These symptoms are caused by the poison injected by the insect, they are normal and mostly harmless.

In allergy sufferers, however, the immune system reacts excessively and defends itself against certain protein components of the poison. Such an overreaction can disrupt the entire cardiovascular system and become life-threatening.

According to the German Allergy and Asthma Association, around one to five percent of adults in Germany have a severe insect venom allergy and need appropriate emergency medication. Up to 25 percent of the adult population and up to 50 percent of children show at least increased local reactions to insect venom.

Most often, an insect venom allergy occurs after wasp and bee stings. Allergic reactions to bumblebee and hornet stings are less common.

The first trick is not yet dangerous

An insect venom allergy does not usually develop with the first bite. It is even possible that someone does not show an excessive reaction to insect bites for years and then the immune system suddenly seems to overreact.

The fact that the body of people with a corresponding disposition is becoming more and more susceptible, and the allergy worsening from sting to sting, is due to the fact that the immune system goes through a sensitization process. It gives the body the signal to produce antibodies against certain proteins and amino acid compounds in the insect venom.

With the next bite, the immune system or the antibodies “remember” these foreign substances, the so-called allergens, and activate a whole cascade of defense mechanisms - the immune system reacts excessively. The allergic reaction spreads from the skin to the whole body.

Insect venoms also contain enzymes such as hyaluronidases and phospholipases, which further distribute the venom throughout the body. The body's own messenger substances histamine and serotonin, which are released in response to the insect bite, expand the skin vessels. Histamine also causes severe itching.

Insect venom allergy: symptoms

In the case of an insect bite, the injected poison causes painful redness and swelling around the puncture site. There is usually severe itching. Usually symptoms resolve within a day. If the swelling is larger than ten centimeters in diameter and lasts longer than a day, experts speak of a severe or worsened local reaction.

First signs of a severe allergy

The first sign of a severe allergic reaction (anaphylaxis) is often a tingling sensation in the palms of the hands, scalp or tongue. The skin becomes red and the affected area swells.

If the allergic reaction spreads to the whole body, shortness of breath, circulatory problems (such as dizziness, rapid heartbeat) and / or stomach and intestinal problems can occur. Various proteins affect the central nervous system, which can lead to drowsiness and nausea. In severe cases, the cardiovascular system breaks down completely.

Such an anaphylactic reaction very often has two phases. Symptoms such as slight shortness of breath, nausea or dizziness often begin minutes after the bite and then gradually subside. A reaction occurs again after a few hours. This can then take on much more severe forms and even be life-threatening.

Can mosquito bites also trigger allergic reactions?

Since the mosquito poison contains certain substances against which the human immune system can form antibodies, it is not uncommon for an allergic reaction to mosquito bites to occur. Mosquitoes or horseflies usually trigger an allergy that is limited to the skin. The puncture site swells over a large area, itches, is red and overheated. The cardiovascular system is extremely rarely affected. Symptoms often last longer than a day. A scar may remain at the puncture site after it has healed.

Insect venom allergy: causes and risk factors

There are a few factors that increase your risk of being allergic to an insect bite:

Previous allergic reactions: An insect venom allergy can develop even if there is no genetic allergy. Anyone who already has another allergy (e.g. to pollen) is therefore no more susceptible to an insect venom allergy than non-allergic people. But: An earlier allergic reaction to an insect bite can increase the risk of severe allergic insect venom reactions.
Frequent contact with insects: People who come into contact with bees or wasps more often and are therefore more likely to get a sting are particularly at risk for an insect venom allergy. These include, for example, beekeepers, gardeners, farmers, fruit and baked goods sellers.
Age: People over the age of 40 have a higher risk of an insect venom allergy than younger people.
Underlying diseases: People with asthma or cardiovascular diseases are more at risk for an insect venom allergy. Mastocytosis is a particularly high risk - a rare disease in which the body has a large number of or altered mast cells (certain immune cells). They heat up the excessive immune defense even further.
Certain medications: Certain medications such as beta blockers or ACE inhibitors, which are used to treat heart disease and high blood pressure, can also increase the risk of insect sting allergies or worsen the allergic reaction.

Allergy trigger in insect venom

In the case of an insect venom allergy, the immune system has formed antibodies against actually harmless components of the venom. Such allergenic substances are called allergens. So far, six different wasp allergens, twelve bee venom allergens and two hornet and bumblebee venom allergens are known.

The most important allergy triggers in insecticide are:

allergic reaction to wasp sting: phospholipase A1, hyaluronidase and antigen 5
allergic reaction to bee sting: phospholipase A2, hyaluronidase, acid phosphatase, serine protease
allergic reaction to mosquito bite: salivary protein rAed a2

Insect venom allergy: examinations and diagnosis

If there is a suspicion of a bee or wasp venom allergy, the doctor will first ask the following questions in the initial consultation (anamnesis):

Which insect stung you?
What were the symptoms after the sting?
Have you been stung by a bee or wasp before? What complaints did you have at that time?
Do you suffer from any chronic illness?
Are you known to have any other allergies?
Do you take any medicine?

This is usually followed by a physical examination, a so-called prick test, and blood tests.

Prick test

In a prick test, the doctor applies various allergens (e.g. from bee venom) in the form of drops to the inside of the forearm. Then you have to wait and see whether the affected areas of the skin show reactions such as reddening or swelling. These indicate an allergic reaction. In the case of a bee sting allergy, for example, the skin on which the bee venom was applied turns red. Sometimes the doctor injects the allergens under the skin.

Detection of antibodies in the blood

If there is an insect venom allergy, the antibodies that the immune system has produced against the allergens of the insect venom are often in the blood. The examination can corroborate the suspicion of an insect venom allergy. Since the antibodies can also be found in the blood for other reasons, their presence is not proof, but only a further indication of an insect venom allergy.

Insect venom allergy: treatment

It is particularly important for people with an insect venom allergy to avoid insect bites as much as possible. Since this does not always work, those affected should always carry an allergy passport and an emergency kit with them.

Therapy of the local skin reaction

If the sting of the insect is still in the skin, a helper or doctor should carefully pull it out so that more poison does not get into the body.
Cool the puncture site with moist compresses, cool packs or ice cubes. Cooling ointments or gels soothe the itching. If there are pronounced skin reactions, an antihistamine can be taken, if present. It inhibits the effects of histamine, thereby relieving allergy symptoms. After that, it is advisable to consult a doctor.
If there is insect bites in the mouth (e.g. on the tongue), ice cubes can relieve the pain (caution - do not swallow!). In any case, a doctor should be consulted immediately or the emergency services should be alerted - pronounced swelling of the mucous membranes can cause breathing problems.

If you get an insect bite in your mouth, you shouldn't give the person anything to drink - the swelling of the mucous membrane could easily make them choke.

Therapy of the body's allergy symptoms

The emergency kit contains medication that the person concerned can use in an emergency before the doctor arrives:

In the event of breathlessness, a spray is available that dilates the bronchi and allows the person affected to breathe deeply again.
For circulatory problems, adrenaline can be administered via an auto-injection syringe. Some people affected can do this themselves, in other cases a helper can do it.
In addition, an antihistamine and a drug containing cortisone are usually included in the emergency kit, which can help alleviate the symptoms.

People with severe allergic symptoms have to go to the hospital and usually stay there for some time to be monitored, as physical reactions can occur later.

Desensitization

Some allergies can be treated with so-called desensitization. Over the course of several sessions, the allergy sufferer receives increasing amounts of the allergy trigger. In this way, the immune system should slowly become “used” to the allergen. This can significantly reduce an insect venom allergy over time. But: Desensitization is a lengthy process and not suitable for everyone, for example, the allergy trigger must be precisely known.

Insect venom allergy: disease course and prognosis

In most cases, hypersensitivity reactions to insect venom do not leave any lasting damage. In Germany, however, there are around 20 deaths each year due to an allergic reaction to insect bites. The number of unreported cases is likely to be higher, since anaphylaxis as the cause of death often remains undetected.

Desensitization can have a beneficial effect on the course of the disease. Long-term protection against an insect venom allergy has been proven especially in children after such therapy. In general, the success rate of desensitization in wasp venom allergy sufferers is 90 percent, and in bee venom allergy sufferers 80 percent.

Preparations for the desensitization of bumblebee or hornet poison allergy are not available in Germany. In the case of a bumblebee venom allergy, however, bee venom preparations can be used, and in the case of hornet venom allergy, wasp venom preparations - the respective poisons are very similar, which is why those affected often have a cross allergy (e.g. many bumblebee venom allergy sufferers are hypersensitive to bee venom).

Avoid insect bites

Furthermore, allergy sufferers should avoid bees, wasps, hornets and mosquitoes if possible. The following measures can help to keep insects away, especially in the warm season:

Do not eat food and drinks outdoors in summer, if they do, be careful and clear away the food and the used dishes immediately afterwards
Do not drink from open bottles or beverage cans, especially outdoors, cover glasses
Do not stand in the vicinity of rubbish bins, rubbish bins, animal enclosures or windfalls
do without perfume or perfumed cosmetics
do not make hectic movements when bees, wasps, bumblebees or hornets are around
Protect the body with clothing, preferably in lighter colors
do not walk barefoot or with open shoes across the meadow

Measures to avoid mosquito bites are:

Fasten window grilles and mosquito nets
Use repellent against mosquito bites (mosquito repellents)
wear long clothes with solid fabrics

The risk of being stung by an insect is particularly high between April and November. During this time it is particularly important that you always have an emergency kit and allergy pass with you if you have an insect venom allergy.

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