While fatal insect stings are rare, knowing what to do after being stung
and when to get medical aid is crucial, especially for those at risk of more serious adverse reactions.
Issue 5 | June 2024
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Insects such as bees, wasps or hornets may be smaller than a human thumb, yet their stings can pack a punch. Sometimes, a deadly punch. It was reported in 2022 that a 60-year-old man succumbed to multi-organ failure as well as ischaemic heart disease after being stung by hornets.
While such fatal incidents may not be heard of very often, insect stings can be a hazard. Last year, 265 patients—three-quarters of whom were children—were seen for insect bites or stings at the National University Hospital (NUH)’s emergency department and children’s emergency. Five patients required hospitalisation for further treatment.
“Insects typically sting to defend themselves or if their hive is disturbed or threatened,” says Dr Jonathan Tang, Consultant with the Emergency Medicine Department at NUH. “At the same time, recognising the danger and knowing when to seek help is crucial, particularly for severe reactions such as anaphylaxis or toxic envenomation, which can rapidly progress and require immediate medical intervention.”
1. What are some insects that have nasty stings?
The most severe reactions are often caused by insects of the Hymenoptera order, which includes bees, wasps, hornets and certain stinging ants like needle ants and fire ants. Hornets, in particular, are known for their aggressive behaviour and potent venom. They can inflict multiple stings, injecting a larger amount of venom per sting compared to bees or smaller wasps, which can lead to severe health complications.
The venom of Hymenoptera insects contains histamine, a chemical that triggers an allergic response, and melittin, which causes pain. It also contains proteins such as phospholipase and hyaluronidase that can be toxic to human cells.
2. How does the human body react to insect stings?
Reactions can vary widely. Most individuals experience a mild local reaction characterised by pain, redness and swelling at the sting site, which typically resolves within 24 hours. Some may experience large local reactions with significant swelling of more than 10 centimetres, which can take up to a week to subside.
In severe cases, such as anaphylaxis or toxic envenomation, symptoms may include low blood pressure, circulatory collapse or airway swelling, which causes suffocation.
3. Who is at risk of severe reactions?
Individuals who have been previously sensitised to Hymenoptera venom (history of severe reaction) are at higher risk of developing anaphylactic reactions. Those with pre-existing allergic conditions such as asthma are also at risk. There is a danger of systemic envenomation in those who received a significant dose of venom (more than 50–100 stings). This has a delayed onset unlike anaphylaxis which occurs early, manifesting 24-48 hours later with multi-organ failure.
“For those who have had an allergic reaction to insect stings, they should carry an EpiPen containing adrenaline that can be administered immediately, if necessary,” advises Dr Tang. “These patients should also be reviewed by an allergy specialist.”
Adults, especially the elderly and those with underlying chronic lung and heart diseases, or those taking certain medications like angiotensin-converting enzyme inhibitors used for high blood pressure or heart conditions, are also more susceptible to severe reactions from insect stings.
4. How can I avoid insect stings?
Keep an eye on your surroundings and be cautious around areas where insects are commonly found, especially near nests. If you spot a wasp nest or beehive near or in your home, do not attempt to remove it yourself—instead, contact a professional pest control company for assistance. Apply insect repellent and avoid applying strong fragrances that can attract insects when going outdoors.
5. What immediate actions should I take if I get stung?
A. Move to a safe area to avoid further stings.
B. Do not attempt to suck out the venom, as this can risk tissue damage.
C. Scrape the stinger sideways using a card or fingernail to prevent further venom release. Avoid pinching or squeezing the stinger, as this can inject more venom into the wound.
D. Wash the site with soap and water, apply a cold pack to reduce swelling and use antihistamines if necessary for relief. Paracetamol or ibuprofen can be taken to relieve pain and inflammation.
6. When should I get medical aid or call for an ambulance?
Consult a general practitioner if you see signs of infection, for example, increased pain, swelling, redness or fever.
“Seek medical attention immediately if you experience symptoms of anaphylaxis, which may include swelling of the tongue or throat, breathing difficulties, vomiting, diarrhoea, abdominal pain, rapid heart rate, confusion or collapse,” says Dr Tang.
These symptoms can happen immediately, within minutes, or up to a few hours after the sting. Patients who have been stung for more than three times should also seek medical attention at the emergency department.
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