Insect stings: normal reaction or emergency?
Local swelling versus a whole-body reaction
Dr. Émilie Garnier
Allergist
In simple terms
How to judge a sting, and who should carry an adrenaline pen.
The normal reaction
Pain, redness and swelling at the site, sometimes a few centimetres across, lasting a day or two. Unpleasant but not dangerous. Cold compress, cleaning, and an antihistamine if itchy.
A large local reaction
Swelling over 10 cm around the site, peaking at 48 hours and lasting several days. Still not an allergy emergency, though it may need a short course of steroids if it limits movement.
Signs of a systemic allergic reaction
- Hives spreading far from the sting
- Swelling of the lips, tongue or throat
- Wheezing, difficulty breathing or swallowing
- Dizziness, collapse, vomiting
These indicate anaphylaxis. Call emergency services and use an adrenaline auto-injector into the outer thigh immediately if one is available.
After a systemic reaction
Referral to an allergist is essential. Venom immunotherapy is highly effective, reducing the risk of a future severe reaction to a small fraction, and is one of the clearest success stories in allergy medicine.
The words explained
Medical terms used above, in everyday language.
- Immune system
- Your body's defence team: cells that fight germs and repair damage.
When should you see a doctor?
- Your symptoms last more than a few weeks or keep coming back.
- They get worse quickly, or stop you doing everyday things.
- You notice sudden pain, breathing trouble, fainting or bleeding — seek urgent care.
- You already take medication and want to change anything about it.
This article explains general health information. It does not replace advice from your own doctor.
Frequently asked questions
- What is Insect stings: normal reaction or emergency??
- How to judge a sting, and who should carry an adrenaline pen.
- What are the main symptoms or signs of Insect stings: normal reaction or emergency??
- Common signs vary from person to person. The article above lists the symptoms to watch for, how they progress, and when they need medical attention.
- When should you see a doctor for Insect stings: normal reaction or emergency??
- See a doctor if symptoms last more than a few weeks, get worse quickly, stop you doing everyday things, or if you notice sudden pain, breathing trouble, fainting or bleeding.
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