July 2025 |  ✓  Medically Reviewed by: Magnus Borres, Director of Medical Affairs

Allergy to insect stings is a problem that affects many people worldwide. Although in most cases the stings only cause mild discomfort, in some individuals they can trigger allergic reactions that can even be severe. Understanding the symptoms, knowing which insects may be responsible, and recognizing the available diagnostic tests available are key steps towards managing this condition more effectively.^1,6

Allergy to insect stings and bites: The venom is to blame

The term hymenoptera refers to a large order of insects. In Europe, 70.6% of anaphylactic reactions are caused by a wasp sting, 23.4% by bees and 4.1% by hornets. Vespula wasp allergy is the most common worldwide.¹¹

When a hymenoptera stings, it injects a venom containing proteins¹ that can trigger reactions in the human body. Reactions to hymenopteran stings are classified as allergic and non-allergic.⁵

The former occurs in sensitised subjects and may be either local or systemic.

Non-allergic reactions are related to the toxicity of the venom and can result in symptoms such as fever, widespread reddening and, in rare cases, acute kidney failure or muscle damage.^3,8

Symptoms of insect bite allergy: The most common allergic reactions to the venom

Allergic reactions to hymenoptera venom fall into three main categories:

• Local reactions: reddening with itchy swelling at the venom inoculation site. These usually clear up within a few hours.^6,7
• Large local reactions (LLR): swelling may exceed 10 cm and persist for up to a week. These often involve the entire body segment affected.^3,7
• Systemic reactions: these involve organs other than the sting site and may present as hives, angioedema, asthma attacks, gastrointestinal symptoms and, in more severe cases, anaphylaxis.^1,7

Prevention of insect stings

Preventing insect stings, together with allergy testing, is the first step towards reducing the risk of allergic reactions, especially for those who have already experienced allergic episodes due to hymenoptera venom.^1,3

A few daily precautions can help minimise insect exposure and avoid potentially dangerous situations.

Here are some tips:

• Avoid strong perfumes and brightly coloured clothes.
• Do not walk barefoot in wildflower meadows.
• Do not drink from cans or glasses outdoors without checking their contents.
• If you are allergic, always carry your adrenaline auto-injector with you.^5,6,7

Knowing the signs of an insect sting allergy and how to deal with it is of paramount importance to preventing serious consequences and living more safely.³

What is responsible for these allergies?

The hymenoptera relevant for allergies belong primarily to the Apidae and Vespidae families:³

• Bees (Apis mellifera) and bumblebees (Bombus terrestris): the bee sting is serrated and remains embedded in the tissue of the victim, causing the death of the insect.^3,4,7
• Wasps (Vespula, Dolichovespula, Polistes) and hornets (Vespa crabro): their sting is smooth, so they can sting several times without losing their lives.^4,5,7
• Red ants: present in some geographical areas, they can inject venom, causing symptoms in sensitized patients.⁸

Allergy testing for insect bites

To diagnose a hymenoptera venom allergy, the patient’s medical history must be taken and specific tests run.^1,5

The aims of the diagnosis are:

• To classify the type of reaction
• To confirm the IgE-mediated pathogenetic mechanism
• To identify the stinging insect^1,5

The diagnosis is based on the patient's clinical history and the results of the diagnostic tests.^2,9,10 The medical history is an essential step, as it allows the patient to describe the symptoms, the course of the reaction (possibly documented by medical certification), the number of stings received and the characteristics of the stinging insect, if recognisable.^1,3

In some cases, it may be helpful to show the patient an entomological display board to facilitate identification of the insect responsible for the reaction.^3,4

One of the most accurate diagnostic tests is the Specific IgE test, which measures the concentration of specific IgE antibodies against the insect venom.^1,2,10

This test offers several advantages:

• Reliability: it provides accurate results for identifying sensitisation to allergens.
• Ease and accessibility: it can be performed at any age, regardless of skin condition or the use of antihistamines.
• Detailed information: it allows cross-reactivity with other allergens to be identified and a customised treatment plan to be developed.^2,3,9,10

Additionally, measuring baseline serum tryptase levels can help identify patients at increased risk of severe systemic reactions and may indicate underlying mast cell disorders, such as systemic mastocytosis.^3,10 This information is crucial for tailoring appropriate management strategies, including the consideration of lifelong venom immunotherapy in high-risk individuals.^1,2,5