Introduction Demographics Causes Clinical features Complications Diagnosis Differential diagnoses Treatment Outcome
Bees (Apidae) and wasps (Vespidae) are venomous stinging insects (class Hymenoptera). A honeybee mostly only attacks when it feels threatened, inflicting a single painful toxic sting. The Africanised ‘killer’ bee, however, is highly aggressive, resulting in massive bee attacks throughout most of the Americas where it has become endemic. Wasps also are aggressive, sting to attack, and can sting multiple times.
Bee and wasp stings mostly occur outdoors, usually around the home. Beekeepers are particularly susceptible, typically receiving many stings over their working lifetime.
In Europe, the prevalence of systemic reactions to bee and wasp stings in the adult population is 0.3–8.9%, higher in beekeepers, lower in children, and are a major cause of anaphylaxis accounting for nearly 50% of adult cases and 20% in children.
The bee stinger consists of muscles, piercing stylet and lancets, and the venom sac, glands, and bulb. Barbs on the lancets make it impossible for the bee to retract its stinger, leaving the stinger embedded in the wound after the bee escapes. An individual bee therefore can only sting once and dies within a day or two. At least 90% of the venom is delivered in the first 20 seconds. Melittin is the most toxic compound in bee venom, causing most of the pain but only minor allergic reactions. Hyaluronidase is a potent allergen and is responsible for the rapid distribution of the venom in tissues.
Wasps can sting multiple times as they do not leave their stinger behind in the skin.
The severity of the reaction depends on the age and size of the victim, the number of stings, previous sensitisation, and co-morbidities such as atopy, mastocytosis, and immune status.
Diagrams from: Pucca MB, Cerni FA, Oliveira IS, et al. Bee updated: current knowledge on bee venom and bee envenoming therapy. Front Immunol. 2019;10:2090.
A bee or wasp sting causes an immediate sharp pain that usually only lasts for a few seconds, followed by redness, swelling, pain, and, following a bee sting, the embedded stinger.
Allergic manifestations
Systemic toxic reactions (envenomation)
Both skin testing and serologic tests should be performed on patients with a history of a systemic reaction to a bee or wasp sting, and considered for those with large local reactions.
If the reaction is mild, bee stings should be treated by first removing the stinger:
Treatment of the sting site:
If a bee or wasp sting causes a severe reaction or anaphylaxis, urgent medical attention should be sought.
In the Americas where the Africanised bee has become endemic, any individual who has had more than 50 stings (‘massive stinging’) should be observed for anaphylaxis and toxic envenomation.
Gradually increasing doses of insect venom are injected subcutaneously to induce immunological tolerance every few weeks for 3–5 years; continue lifelong in clonal mast cell disorders with history of severe reaction or very severe anaphylaxis reactions. Protection usually lasts 1–3 years after discontinuation.
Insect venoms are commercially available for honey bee, paper wasp, and yellow jacket European wasp.
A Cochrane review reported venom immunotherapy significantly reduces the risk of systemic and large local reactions, and is likely to reduce the risk of anaphylaxis, improving quality of life.
Venom immunotherapy can be recommended for:
The majority of bee and wasp sting reactions are localised and resolve in hours to days. Episodes are usually rare and simple preventative measures are all that is required. However, sensitisation can develop with repeat episodes, such as can happen to beekeepers and agricultural workers. Following an episode of anaphylaxis, the risk of subsequent anaphylaxis is less than 50%, lower in children.
