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Insect bites and stings

Patient information A-Z

When you are bitten or stung the insect injects a form of saliva into your skin that can lead to symptoms of inflammation (redness, swelling, pain and warmth) or local irritation. Symptoms vary depending on the insect involved, and the sensitivity of each individual. A bite or sting often causes a small, itchy lump to develop. Bites and stings usually clear up within several days and can be safely treated at home.


Antihistamine tablets

Antihistamine tablets such as chlorphenamine and skin creams which help stop itching can be bought from local pharmacies. If you regularly take other medicines please check with your doctor or pharmacist.

Pain relief

Painkillers like paracetamol can help relieve any pain. Anti-inflammatory tablets such as ibuprofen can also be very helpful if you can take them. If in doubt about whether you can take them check with your pharmacist or doctor.

Hot water immersion

immersing the bite and surrounding area in warm or hot (non-scalding!) water can reduce pain and initial swelling.


Regular application of ice-packs can relieve symptoms of inflammation (wrap ice-packs in a wet cloth to prevent skin burns)


Elevating affected limbs can help to minimise swelling.

Try not to scratch. This may lead to a skin infection.

Minor allergic reactions

Some people may have a localised allergic reaction at the site of the bite or sting in the form of a swelling that becomes larger over several hours and gradually decreases over a few days. Swelling size can vary from a few centimetres to an entire arm or leg.

Skin infection

Occasionally a skin infection develops two to three days after a bite or sting, particularly if you scratch the area. Scratching breaks the skin’s surface allowing bacteria (germs) to get in. Infection causes redness and pain around the bite. This may spread over several days and may require treatment.

Symptoms of skin infection

Rapidly increasing swelling and redness or a redline tracking upwards from the affected area.


  • The skin is hot to touch
  • Pus in or around the bite/sting
  • Swollen glands
  • Flu-like symptoms

If you suspect you are developing a skin infection you should seek medical attention from your GP on the same day or the emergency department as you may require antibiotics.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151