Testing for Insect Venom Allergy: background and complications

Updated: Apr 28, 2022

When testing for an insect venom allergy, it is important to understand the background, as well as potential complications and interference. Reviewing all aspects is the foundation for making reliable clinical decisions.

“Common insects that sting with venom include bees, wasps, ants, hornets, bumblebees. Typically, we see allergies from insects that have 3 pairs of legs, either creeping or flying, or insects that also have the characteristic of living in community” informs Dr Habib Chabane, Allergist in Paris.

Insect venoms:

Every spring, most stinging insects establish nests where the queen keeps busy reproducing. By the time summer arrives, nests have experienced a population explosion and hundreds to thousands of wasps, hornets, ants, or bees are moving around properties. By the time fall arrives, natural food sources that may have sustained the growth of the nest start to run out. Flowers and other insects are not as abundant as the weather grows colder, leaving stinging insects to seek out alternatives. Unfortunately, this often leads to them becoming more of a problem at BBQs on the deck, picnics on the lawn, and other outdoor events. Get too close and you may be met with a painful sting that leads to an uncomfortable red welt. And for those allergic individuals, the symptoms can quickly escalate to severe pain, swelling, and even anaphylaxis, which can be life-threatening without immediate treatment. Bees tend to be the main insect responsible for anaphylaxis, as they inject 5-10 times more venom than wasps.

The difficulty reliably testing for insect venom allergy:

When using venom extracts during allergy testing, an individual’s sensitization is related to their exposure to low molecular weight substances within those extracts; that person can either react to clinically relevant allergenic proteins or to clinically irrelevant cross-reactive carbohydrate determinants (CCDs) that are present. In insects, the CCD epitope is simply alpha-1,3-linked fucose (sugar) residue that is part of the carbohydrates attached to most proteins that are present in the venom. Because these carbohydrate molecules are not found in humans, they become highly immunogenic and thereby produce elevated levels of IgE antibodies that can be detected during testing. Unfortunately, that reactivity obscures and in many cases, doubles the reactivity seen in sensitized patient results, making them only partially reliable in diagnosing a patient’s underlying reactivity. Therefore, many clinicians have turned to CCD-free allergenic materials (components) rather than extracts to more accurately determine a patient’s reactivity to venoms.

CCD-free components in allergen testing:

The venom of the common honeybee (Apis Mellifera) is probably the best characterized in the clinical laboratory. Over the past few years, more than 100 proteins have been identified in venoms including major allergic proteins like Phospholipase A2 (Api m 1), Hyaluronidase (Api m 2), Acid phosphatase (Api m 3), Dipeptidyl Peptidase IV (Api m 5) and the Carbohydrate-rich protein Icarapin (Api m 10). These components are devoid of carbohydrate-based cross-reactivity which allows a clinician to determine the role of a particular allergen without the noise created by CCD interference. More research into these components is clearly needed to help determine whether certain sensitization profiles to an individual major allergen can be linked to the severity of reaction or the predictive outcome of immunotherapy. Learn more about CCD interference in allergen testing

Can Immunotherapy help patients with venom allergies?

Immunotherapy can prevent life-threatening reactions and reduce anxiety associated with insect stings. Immunotherapy for insect sting allergies is a series of allergy shots given to reduce your sensitivity to allergens that cause the allergic reaction. Small doses of allergens are injected over time under the skin and can reduce the severity of the reaction to the venom. Immunotherapy for insect stings has been shown to reduce the chance of successive systemic reactions from ~60% to about 5%. The shots are safe if given correctly with the most common side effects being redness and warmth at the shot site. Some people may have large local reactions that include itching, hives, or swelling near the shot location. More serious but less common side effects include hives, itching, or difficulty breathing. In rare cases, a person may have a severe allergic reaction (anaphylaxis) to the shots. Because of this possibility, the shots are given in a doctor's office or another setting where emergency care can be provided if needed.

When testing for insect venom allergy, getting the right answers matters. NOVEOS® the new standard in allergen testing in order to limit the impact of interferences. Learn more about how NOVEOS is solving the shortcomings of current allergy testing.