Author: Dr Beth Wright, Core Medical Trainee, Bristol, United Kingdom, 2013.
Insects that sting are members of the hymenoptera class of insects:
The stinging apparatus is located in the abdomen of the female insect and consists of a sac containing venom and a barbed stinger.
When a bee stings, the apparatus becomes detached from the insect leading to its death, hence bees can only sting once. However wasps can sting multiple times and do not leave their sting behind in the skin.
A sting from a wasp causes a sharp pain that usually lasts for a few seconds. The area that has been stung often become red, painful and swollen. It may cause local irritation, itching or pain for hours to days afterwards.
A sting from a bee feels similar to that from a wasp however it leaves a sack, filled with venom in the skin.
Most people suffer only minor symptoms after a sting. However some people suffer more severe or even life-threatening reactions.
Life-threatening allergic reactions due to anaphylaxis are rare. They are more likely in people that have been stung before, because of sensitisation to the insect venom.
A bee's sting should be removed immediately from the skin. As a wasp does not leave its sting behind you cannot remove it. Avoid squeezing more venom from the sack of a bee sting into the skin when trying to remove it with fingers or tweezers. It is best scraped off with a flat card.
The severity of the reaction will determine if any medical treatment is needed.
A large localised reaction with severe swelling may warrant a course of oral steroids, for example prednis(ol)one for 3-5 days.
Life threatening reaction or anaphylaxis is a medical emergency.
Bee and wasp sting reactions are sometimes very persistent, lasting weeks or months.There have been case reports of vasculitis, serum sickness, neuritis and encephalitis occurring in the days to weeks following insect stings. There are even reports of secondary parkinsonianism following hymenoptera stings and cerebral infarction. Some of these have occurred after anaphylactic reactions to stings.
Skin prick tests and serological reactivity testing can be performed to identify those who may suffer more severe reactions from insect stings. This is useful to identify where venom immunotherapy (VIT) would be of benefit.
Venom immunotherapy (VIT) is an effective treatment to protect venom allergic people from sting-induced anaphylaxis. It is not generally indicated for adults with systemic reactions limited to the skin (eg, urticaria, angioedema or erythema).
Venom immunotherapy is usually performed by an immunology or allergy specialist. It involves a course of injections containing a very small amount of the allergen, which in this case is insect venom. The injections are given under the skin repeatedly over a prolonged period of time, often several years. The amount of venom injected is slowly increased throughout the course. Eventually desensitization occurs, meaning the body becomes less sensitive to the venom.
Simple measures can be taken to reduce the risk of being stung by these insects:
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