Allergy to insect venom
Hymenoptera venom allergy is a violent and severe allergic reaction in the body that occurs after being stung by a bee or other insects. This violent allergic reaction can also lead to anaphylactic shock, which is an immediate life-threatening condition. It is therefore estimated that an allergy to insect venom underlies about 20% of deaths resulting from anaphylactic reactions in Poland. The allergy to the venom of hymenopterous insects is the most common, and these include:
- bees: honeybee and bumblebee
- wasp group: common wasp, wasps of the species Dolichovespula and the hornet,
- in recent years, insects from the family of ants, which also belong to the Hymenoptera, have become increasingly important.
Which insects are classified as hymenoptera?
Hymenoptera, represent more than 153 000 species worldwide. Well, maybe not quite – they are not found in the polar regions. However, tropical countries are where most of them are recorded. Hymenoptera include, among others, bees, wasps and ants (Fig.).
Among Hymenoptera, the most significant insects in terms of allergies in our geographical region are those whose venom is most commonly responsible for allergic reactions in humans. These include representatives of the families Vespidae (wasps) and Apidae (bees). Among them are wasps, honeybees, hornets, and bumblebees.
Wasp, honeybee, hornet and bumblebee – appearance and habits
| Insects | Bees | Wasps | Bumblebees | Hornets |
| Body length approx. | 15 mm | 10-20 mm | 8-18 mm | 18-35 mm |
| Appearance | Brown-yellow thorax covered with dense hairs | Yellow-black colouring, smooth, slender thorax with characteristic narrowing (so-called wasp waist) | Spherical, heavily hairy body, broad orange or yellow stripes | Yellow-brown-red colouring with black pattern, almost hairless thorax |
| Nutrient | Nectar and pollen | Nectar, fruit, insects | Nectar and pollen | Nectar, fruit, insects |
| Importance in nature | Pollinates plants, produces honey | Pollinates plants, regulates populations of other insects | Pollinates plants | Pollinates plants, regulates populations of other insects |
| Sting | Present only in females, armed with hooks, after the bee stings, the stinger remains in the body of the victim, stings only once | Present only in females, smooth, does not remain in the skin, wasp can sting repeatedly | Present only in females, smooth, sharp and long, does not remain in the skin | Only present in females, smooth, does not remain in the skin |
| Grade of aggression | Non-aggressive – do not attack for no reason | Do not attack for no reason but are “curious” and like to fly close to people | Gentle, only attack in self-defence | When they do not feel threatened they do not attack – they are only aggressive when attacked |
| Behaviours that increase the risk of stinging | Walking barefoot on grass, beekeeping, staying close to nectar, pollen and sweets | Staying close to food and rubbish bins | Walking barefoot on grass, being close to nectar, pollen and sweets | Staying near hornets’ nests, threatening insects, destroying nests |
| Habitat and habits | House hives, wax comb nests in hollow cavities | They build their nests out of paper pulp-like material. The location of the nest depends on the species – in the ground, hollows, building elements, trees or shrubs | Wax nest resembling a bunch of grapes, located underground, e.g. in abandoned burrows of small rodents | Large (up to 50 cm long and high) brittle nests of paper pulp-like material in hollow tree trunks and inside buildings |
What Hymenoptera venom is made of
Hymenoptera venom is the secretion of special insect venom glands. As an ‘attack-defence’ substance, it has two functions: it is used to defend against an attacker and to obtain food (it paralyses the attacked insects).
The venom is injected into the body of the attacker or victim using a specialised stinging apparatus located at the end of the appendix.
From a chemical point of view, hymenoptera venom is a mixture of many biologically active substances with various physiological functions. It is also characterised by specific effects on the organism of the animal or human being stung by the bee or other insects. Many of them have the properties of enzymes that break down cell components, as well as compounds with toxic effects (including the so-called neurotoxins).
Many of the substances contained in hymenopteran venoms also have allergenic properties. The most important, from the point of view of the diagnosis of allergy to hymenoptera venoms are: bee venom allergens (Api m 1, Api m 2, Api m 5 and Api m 10) and wasp and cockatiel venom allergens (Ves v 1, Ves v 5 and Pol d 5).
When bees and other Hymenoptera sting
In a temperate climate, bee stings and those of other Hymenoptera occur from early spring to late autumn. The peak bee activity takes place from mid-July to the end of August. As for more aggressive species like wasps, their activity spans from late July to the first decade of September. Hornets and bumblebees sting very rarely, sporadically. Stings can also occur during winter, for example, if accidentally disturbed wasp nests in an attic. Incidents of bee and wasp stings during night-time hours are not observed due to their natural inactivity during that time.
Reaction after a sting: allergic versus non-allergic person
Given that hymenopterous insect venom is a mixture of highly toxic substances with a highly irritating effect, it is important to remember that not every reaction after an insect sting is an allergy.
- In people who are allergic to hymenoptera venom, the sting of a single insect is enough to cause symptoms of the disease. In this situation, the allergic reaction after a bee or other insects sting can be the so-called major local reaction or a general (whole body) reaction, also severe and life-threatening. Most often, the development of symptoms occurs within a few minutes to a few hours. Some patients, after initial improvement, may experience recurrence of symptoms within several hours.
- In people who are not allergic to venom, the sting of a single insect does not cause any significant reaction. Often there is a local reaction. This takes the form of a large, painful swelling with redness (even over 10 cm in diameter), which usually subsides within 24 hours. It may be accompanied by itching or burning. If there is an infection at the sting site, the reaction may be protracted. In this particular situation, fever or the enlargement of nearby lymph nodes may occur.
A local reaction is not usually life-threatening unless it involves the head, face, neck or the inside of the mouth. Then swelling of the tissues can lead to suffocation.
- On the other hand, when stung by multiple insects at the same time (what we call a cluster sting), toxic symptoms, including life-threatening ones, can occur.
A few important points
- After an insect stings, it is worth paying attention to the appearance of the insect and whether the sting remains in the skin.
- It is a good idea to wash the sting site with plenty of soap and water, and to apply a cold compress.
- People who know they are allergic to insect venom should be equipped with a first aid kit (antihistamines, oral corticosteroids and adrenaline).
- Observe the person being stung and do not leave them alone.
- If the person begins to feel worse, call for help.
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translation: Julia Majsiak
