Insect venom allergy

Overview: What is an insect venom allergy?

Similar to medication, cat hair, pollen or food, insect bites can also trigger an allergy.
In Switzerland and the rest of Central Europe, the most common causes are bees, wasps or hornets.
Allergies to bumblebee, horsefly, mosquito and ant stings are much rarer.
When insects inject (inject) their venom under the human skin via a sting, it acts as a substance in the blood of the person affected, which is recognized as foreign by the human immune system and combated.
This defense reaction (immune reaction) can be so strong that it produces allergic symptoms, i.e. an allergy.
In the case of allergies, it is therefore not the poison but the excessive reaction of the immune system that triggers the symptoms of the disease.
This reaction of your body does not manifest itself the first time you are bitten by an insect to whose venom you are allergic: Only on the second contact with the insect venom (and on all subsequent contacts) does your immune system react because it now recognizes and fights the allergen.
You may have had previous contact with this venom, for example as a small child, without knowing or remembering it.
You could therefore be surprised by an unrecognized allergy.

Insect venom allergy – frequency and age

Allergies to insect venom are not all that rare; however, the vast majority only experience a strong local reaction after an insect bite: the body only reacts at the site of the bite, i.e. on the surface of the skin and underneath.
In rarer cases, the sting triggers a systemic reaction that affects the body as a whole and can have a severe impact.
The so-called systemic reaction after insect bites occurs in around 1.2 to 3.5 percent of the population.
In Switzerland, around three to four people die from it every year.
In most cases, however, other factors are involved in addition to the allergic reaction, such as existing cardiovascular disease or severe exhaustion.

Insect venom allergy: causes and risk factors

When insect toxins enter your bloodstream, they are foreign bodies (antigens) for your organism.
Defence cells in the blood (antibodies) recognize these intruders and try to fight them.
In this case, they are antibodies of the IgE type (immunoglobulin E).
Their defense mechanism consists of binding to the antigens and thus restricting their activity.
Insect venoms and other antigens that trigger allergies are also called allergens.
If the IgE antibodies recognize the allergen in a second or subsequent sting of the same insect species, the body is prepared (sensitized) and can react immediately to the insect sting.
People with allergic reactions do this to an excessive extent: their immune system reacts too strongly to a substance that is harmless to others.
When antigens (allergens) and antibodies come into contact, certain substances are released in the tissue.
These are hormones or messenger substances that are distributed throughout the body via the blood.
They trigger the allergic symptoms.
An important messenger substance here is histamine.
The venom of bees and wasps contains a number of different allergens, some of which are the same.
The venom of hornets largely corresponds to that of wasps; the composition of the venom of bees is similar to that of bumblebees.
There is also a certain, albeit smaller, cross-reactivity between bee and wasp venom.
There are therefore people who are only allergic to bee or wasp venom and others who are allergic to both venoms.

Symptoms: Insect venom allergy

Sometimes it only takes a few minutes for the first symptoms to appear on the skin after an insect bite.
Non-local reactions (which go beyond the skin) can still occur after 30 minutes.
Not every reaction is necessarily an allergic one: there are people who suffer from a severely swollen arm after an insect bite but do not have an insect venom allergy.
Only a medical diagnosis by means of a blood test (determination of specific IgE against bee and wasp venom) can clarify the situation.

The symptoms of an insect venom allergy can be divided into different degrees of severity

• Local reaction (local reaction): The insect venom causes redness or swelling of the skin in the area of the bite.
  Other common symptoms are itching and burning.
  The area of swelling is less than ten centimeters in diameter and subsides after 24 hours at the latest.
  This reaction, which is externally limited to the skin, can also be accompanied by unpleasant sensations (e.g. dizziness, headache, general malaise).
• Severe local reaction (increased local reaction): The swelling is usually larger than ten centimeters, painful and persists for more than a day.
  As a rule of thumb: Swelling that exceeds the palm of the stung person’s hand is considered excessive.
  If you suffer from this degree of severity of an insect venom allergy, you may also feel a chill or feel ill.
• Systemic reaction (general reaction): In addition to the accompanying symptoms mentioned above, symptoms similar to hay fever may occur (watery eyes, swollen nasal mucosa).
  However, serious and sometimes life-threatening symptoms are also possible: for example, shortness of breath, dizziness, nausea, diarrhea and cardiovascular problems.
• Allergic shock (anaphylactic shock): This is the most severe possible reaction to insect venom – it can be fatal.
  If you initially feel a tingling or burning sensation on your tongue or in your throat after an insect bite (or sting), this may be the first sign of anaphylactic shock.
  If it is not treated immediately, further reactions are possible: rapid heartbeat, vomiting, shortness of breath, excretion of urine and stool, unconsciousness.

Anaphylactic shock: life-saving emergency aid

If you know that you are one of those people who are allergic to insect venom and have severe symptoms, you should carry an emergency kit with you.
You can use it in an emergency without outside help and should have familiarized yourself with it before using it for the first time.
Such a kit usually contains three different, fast-acting drugs, which are administered in liquid form or as a ready-to-use syringe (adrenaline):

• Antihistamine
• Cortisone
• Adrenaline (for injection)

Insect venom allergy: diagnosis with us

When you visit us after an insect bite, we will first ask you questions about the specific incident:

• On what occasion were you stung?
• Have you seen the insect?
• What symptoms have occurred?
• How quickly did they appear?

Other questions relate to comparable experiences in your past:

• Have you ever been bitten by an insect?
• With what consequences?

We may also ask you questions about your lifestyle and dietary habits.
Allergies sometimes take a severe course if their actual trigger (sting or bite) coincides with other factors.
For example, with psychological stress, the consumption of certain foods or the intake of medication (e.g. beta-blockers, ACE inhibitors).
This also needs to be clarified when diagnosing an insect venom allergy.
To find out whether you actually have an insect venom allergy, we may arrange an allergy test.

• The best known is the skin test: In this procedure, insect venoms that are suspected of causing an allergy are highly diluted and brought into direct contact with the skin in small doses.
  Allergic reactions then usually appear in the form of redness and swelling (wheals).
  However, more severe symptoms can also occur, which is why the test should always be carried out under medical supervision.

This skin test can also show whether you are allergic not only to one specific venom, but to several.
For example, if you have developed an allergy to bee venom after a bee sting, a second allergy to another insect venom could occur unnoticed.
In such a case, medical professionals speak of a cross-reaction or cross-allergy.

• The CAP test (cellulose carrier polymer system) is a laboratory test to determine whether your blood contains certain antibodies (IgE antibodies) that are directed against a specific insect venom.
• Further laboratory tests can be carried out to, for example
  • Recognize differences between bee or wasp venom as a trigger
  • assess the possible protective effects of hyposensitization/immunotherapy with insect venom
  • recognize increased risk factors.

Insect venom allergy: prevention, early detection, prognosis

The best way to avoid the threatening symptoms of an insect venom allergy is to protect yourself from insects that are dangerous to you.

The most important measures to avoid insect bites

• Do not walk barefoot outdoors.
• Wear long pants and clothing with long sleeves outdoors.
• Avoid brightly colored clothing because bees can mistake them for flowers.
  (Wasps, on the other hand, are not interested in colors, but in smells).
• Do not rely on insect repellents; they usually do little or nothing to repel hymenoptera that trigger an insect venom allergy.
• Make sure that you do not drink from glasses or bottles that could contain bees, wasps or other insects that are dangerous to you.
• Please note that certain odors attract insects.
  These include sweat, fragrances in creams, hairsprays or soap as well as various foods (meat, ham, fruit, sweets).

If you suffer from mastocytosis (a rare skin or blood disorder that sometimes also involves other organs), please make sure you inform us.
Mastocytosis sufferers have an increased risk of suffering an anaphylactic shock after an insect bite.

Insect venom allergy: prevention through hyposensitization

One method of prevention is to make your immune system less sensitive to the effects of insect bites or stings, to desensitize it.
This is done by first administering very small and then slowly increasing amounts of highly diluted insect venom to your body.
The aim is to get your body used to the venom.
The aim of hyposensitization is to ensure that your body no longer reacts so violently if you are later exposed to a larger and undiluted dose of venom after a sting.
This therapy is called desensitization, hyposensitization or specific immunotherapy.
It usually lasts three to five years.
Initiation begins with a day spent as an outpatient in hospital (so-called ultra-rush); after three injections in the allergy ward, injections are then required every four to six weeks at intervals of several weeks; these can be carried out by your family doctor or by us.
Before we carry out hyposensitization on you, we must ensure that you actually have an allergy and that the triggering allergen (the insect venom) is known exactly.
A further prerequisite is that you have had symptoms after previous contact with this venom (through a sting or bite) that are stressful for you.

Course and prognosis of insect venom allergy

The acute situation: If you are stung by an insect to whose venom you are allergic, the course of your allergic reaction and the consequences depend above all on whether and how quickly treatment takes place.
Untreated symptoms can be harmless but also life-threatening; they can last for minutes or even hours.
The sooner the symptoms of an insect venom allergy appear after a sting, the more serious the complications tend to be – and the higher the likelihood of suffering an anaphylactic shock.
On the other hand, if the symptoms are treated quickly, they often subside quickly and usually leave no noticeable consequences. The long-term situation: If you know that you suffer from an insect venom allergy, the aforementioned hyposensitization can lead to a favourable prognosis.
After careful treatment, your chances are good that annoying or threatening insect sting symptoms will only be less severe in the future.
They may even disappear completely.
Without hyposensitization, an allergy to bees, wasps or other insects often lasts a lifetime.
However, allergies can also become less severe with age.
And they may only appear for the first time later in life.

Insect venom allergy: effective treatment

If you are allergic to insect bites and have been stung, try to pull the stinger out of your skin as quickly but carefully as possible.
If there is a venom gland attached to it, do not crush it, but lever it out from underneath with your fingernail, for example – otherwise more venom could get into your bloodstream.
Beekeepers, who usually have experience with bee stings, flick the stinger out with their fingernail.
At the same time, ask yourself a simple question: are the symptoms mild (and easily tolerated) or so severe that you need professional help?