Stings & Allergy

Wasp Stings & Allergy — First Aid Guide

Most wasp stings need nothing more than ice, paracetamol and an antihistamine. A small minority need 999. This guide tells you exactly how to tell the difference — and what to do in the first 30 minutes either way.

Cold compress being applied to a forearm wasp sting

Call 999 immediately if, within 30 minutes of being stung, the person has: difficulty breathing or wheezing; swelling of the lips, tongue, mouth or throat; a hoarse voice; widespread hives or rash away from the sting site; dizziness, faintness or collapse; sudden severe anxiety with rapid heart rate. These are signs of anaphylaxis. Lay the person flat with legs raised. If they have an adrenaline auto-injector (EpiPen, Jext, Emerade), use it immediately into the outer thigh — even through clothing.

Normal reactions vs allergy — at a glance

Reaction type	What you see	What to do
Normal local reaction	Sharp pain, redness and swelling up to 5cm across at the sting site. Settles over 24-48 hours.	Ice, paracetamol or ibuprofen, oral antihistamine if itchy. No medical input needed.
Large local reaction	Swelling more than 10cm across, may track up a limb. Lasts 3-7 days. Itchy and uncomfortable but not dangerous.	Oral antihistamine, cold compress, elevate limb. GP if it keeps spreading after 48 hours.
Mild systemic reaction	Hives away from the sting site, mild nausea, flushing. No breathing or circulation problems.	Antihistamine immediately. Phone 111 for advice. Do not drive yourself.
Anaphylaxis	Breathing difficulty, throat tightness, voice change, dizziness, collapse, widespread rash. Onset within 30 minutes.	999 NOW. Use adrenaline auto-injector if available. Lay flat, legs raised. Do not stand up.
Delayed reaction (7-14 days)	Fever, joint pain, hives returning, swollen glands.	GP appointment. This is serum sickness — usually resolves with antihistamines and a short steroid course.

What to do in the first 5 minutes

Get away from the nest. If you've been stung once, more are likely. Walk briskly — do not run flailing — at least 10 metres away, ideally indoors.
There is no sting to scrape out. Unlike bees, wasps do not leave a sting embedded. Don't waste time looking.
Wash the area with cold soapy water. Removes any venom on the skin surface and reduces infection risk.
Apply something cold. Wrapped ice, a bag of frozen peas, a cold can — for 10 minutes on, 10 off, for the first hour. Slows venom spread and reduces swelling.
Take pain relief if needed. Paracetamol or ibuprofen at standard adult doses. Avoid ibuprofen on an empty stomach.
Take an oral antihistamine if itchy or swollen. Cetirizine 10mg or loratadine 10mg are widely available.
Sit down for 30 minutes and watch for systemic signs. Don't drive. If anything in the red callout above appears, dial 999.

Multiple stings — when to seek help

Wasp venom is cumulative. The lethal dose for a healthy adult is estimated at 50+ stings, but systemic toxic effects — vomiting, headache, low blood pressure, dark urine — can appear from around 10 stings upwards even with no allergy. Phone 111 for any adult with 10+ stings, or any child with 5+ stings. Multiple stings on the head, neck or inside the mouth always warrant a same-day medical assessment because of airway risk.

If you know you are allergic

Anyone with a previously confirmed wasp venom allergy should carry two in-date adrenaline auto-injectors at all times during summer and autumn, and have an up-to-date allergy management plan from an NHS allergy clinic. If you have been told you are at risk but do not yet have a referral, ask your GP about venom immunotherapy — it is highly effective and reduces future anaphylaxis risk by over 90%.

Pets and wasp stings

Dogs are stung most often on the muzzle, paws or inside the mouth after snapping at a flying wasp. Cats are typically stung on the paw or face. Single stings on the body usually need no more than a cold compress and observation for 24 hours. Stings inside the mouth, throat or that cause facial swelling are an out-of-hours vet emergency because of airway compromise. Multiple stings, any collapse, or persistent vomiting all warrant immediate vet assessment.

Preventing the next sting — practical advice

If wasps appear at your meal, stand up slowly and move indoors. Swatting triggers defensive pheromones that bring more wasps.
Keep drink cans covered. Wasps crawl inside and stings to the inside of the mouth are uniquely dangerous.
Don't walk barefoot on lawns in August or September — underground nests are easy to step on.
Check eaves, sheds and bird boxes early in summer. A nest treated in July is safer and cheaper than one in September.
If you have confirmed venom allergy, avoid scented body products outdoors during wasp season.

If the nest causing the stings is on your property

One sting tends to mean a forager has been disturbed. Repeated stings, or seeing wasps coming and going from one spot on the house, means you have an active nest. Locate it from a safe distance, stop using that part of the garden, and call us. Most nests can be treated the same day and the colony is dead within 24 hours.

Related guides

Frequently asked questions — wasp stings

How do I know if I'm allergic to wasp stings?+

Most people experience a normal local reaction — pain, redness and swelling at the sting site lasting up to 48 hours. An allergic reaction is systemic: hives away from the sting site, swelling of lips/tongue/throat, difficulty breathing, dizziness, or sudden weakness. Systemic symptoms within 30 minutes of being stung mean anaphylaxis — call 999.

Should I take an antihistamine after a wasp sting?+

An oral antihistamine such as cetirizine or loratadine is reasonable for any sting that itches or swells noticeably. It does not prevent anaphylaxis, but it reduces local discomfort. If you have no allergy history, one tablet is sufficient. Always check for interactions if you take other medication.

My child has been stung — what's different?+

Children sting reactions are usually proportionally larger because they are smaller. A sting on the face or near the airway warrants more caution — watch for any voice change, drooling, or breathing difficulty for the first hour. Multiple stings (more than five) in a small child should be assessed by 111 or A&E.

How many wasp stings is dangerous?+

For a healthy adult with no allergy, fatalities from non-allergic mass envenomation typically require 50+ stings. However, anyone receiving more than 10 stings should phone 111 — venom load alone can cause systemic symptoms. Anyone with a known allergy needs medical attention after even a single sting.

My dog was stung — what do I do?+

Single stings on the body cause local swelling and discomfort but are rarely dangerous. Stings to the mouth, throat or tongue are an emergency — the swelling can block the airway. Go to the vet immediately. Multiple stings (over 5) also need vet assessment regardless of location.

Can a wasp sting cause delayed reactions?+

Yes. Serum sickness — fever, joint pain, hives, swollen lymph nodes — can appear 7-14 days after a sting and needs GP review. Local cellulitis (spreading red infection) can also develop 24-72 hours later and needs antibiotics. Persistent worsening at 48+ hours is not normal — see a GP.

Medical disclaimer: This page is general first aid information, not personal medical advice. If in any doubt about a sting reaction, call NHS 111. In a suspected anaphylaxis, call 999 first, ask questions later.

Nest causing the stings? Call 01727 789571 or 0800 046 3473. Same-day across Hertfordshire and North London. Fixed price from £99. Free revisit.