What is insect sting allergy?

It is quite normal to have pain, local redness and swelling at the site of the sting. Some people have large local reactions. A few have generalised reactions. When an insect sting causes a generalised reaction (one affecting the whole body) this is allergy.

What are the symptoms of insect stings?

Not allergy

Local

Redness

Pain

Swelling

Large local

Redness

Pain

Swelling

Allergy

General

Hives

Swelling

Anaphylaxis

Wheeze

Breathing difficulty

Throat tightness

Faint/collapse

Which insects are likely to sting me?

In the UK, bees and wasps are most likely to sting people.

When should I worry about an insect sting reaction?

Local reactions, even if large should not be viewed as an allergy, but rather inflammation caused by the venom in the sting. These patients have low risk of severe allergy. Where local reactions are very large or do not settle medical attention should be sought.

Allergic symptoms occur when the venom from the sting triggers the release of chemicals such as histamine, not just at the sting site but more generally. The risk of allergic reactions is highest if a second sting occurs 2-8 weeks after the first.

People allergic to wasp stings are unlikely to be also allergic to bee stings.

How can I avoid being stung?

People are most likely to be stung in summer and early autumn.

Wasps build nests in sheltered areas including trees and roof spaces. They are attracted to sweetened and flavoured drinks, fallen ripe fruit, and dust bins. Bright colours can also attract them. Carefully removing ripe fruit, well fitting lids on bins and not leaving opened drinks around can help to prevent insect stings. Local councils have provided help in getting rid of nests from homes and gardens.

How serious are insect stings?

The vast majority of insect stings just cause localised reactions. Only a small number of stings lead to generalised allergic reactions.

What should I do if my child is stung?

Bees leave a sting behind in the skin and die soon after stinging. Wasps and hornets do not leave their sting or die after stinging. They can sting again. Walk away calmly to prevent getting stung again.

remove-stingRemove the sting immediately – Remove the sting and venom sac by scraping it out, either with a fingernail, or something with a hard edge such as a credit card, as shown in the picture.

Be careful not to pinch or squeeze the venom sac (e.g. with tweezers) as this might spread the venom further under the skin.

 Local and large local reactions – Wash the affected area with water. Ice packs and raising the part of the body that has been stung can reduce swelling. Avoid scratching the area. Painkillers such as paracetamol or ibuprofen can be given if required. Antihistamines can reduce local itch. The swelling will usually start to go down within a few days. More severe local symptoms also settle down without treatment or with local cold compress and use of these medicines.

Allergy reactions – Seek urgent medical help if any of the following symptoms occur:  difficulty breathing, wheeziness or tightness in the throat; faintness or collapse (anaphylaxis). These severe allergy symptoms can occur with or without hives or generalised swelling.

Hives and swelling can be treated with antihistamines.

Who needs to know about this allergy?

It is important to inform the nursery/school and any after-school clubs. Any other carers such as grandparents, relatives and school friends’ parents will also need to know.

Is insect venom life-long?

Only 10% of children with mild generalised reactions will have an allergic reaction to subsequent stings. This will not be more severe than the preceding sting. Patients who carry an adrenaline pen are usually followed up  at the hospital at yearly intervals.

Unless the child is stung repeatedly over the next few weeks to months the chance of another allergic reaction is about 10%.  Patients are usually assessed again at yearly intervals.

Which patients should be referred to an allergist?

Patients with local reactions, even if large, do not need to see an allergist. Patients who have any generalised allergic reaction after a sting, including those with only a skin rash (hives) should be prescribed and shown how to use an adrenaline pen (auto injector) by their GP and be referred to an Allergist for further tests and treatment. Although adults are sometimes  treated with injection (immuno)therapy, this is only rarely required  in children.

Created May 2011, reviewed Sept 2016

Allergy to Insect Stings  – North West Paediatric Allergy Implementation Group

This information should be used in conjunction with advice from a medical professional

 References

Kristna MT et al. Diagnosis and management of hymenoptera venom allergy: BSACI guidelines. Clin Exp Allergy, 2011.

Lange J. Natural history of Hymenoptera venom allergy in children not treated with immunotherapy. Ann Allergy Asthma Immunol, 2016.