Topic Overview

What are allergies to insect stings?

When you are stung by an insect, poisons and other toxins enter your skin. It's normal to have some swelling, redness, pain, and itching around the sting. But you may have an allergic reaction if your immune system reacts strongly to allergens in the sting.

You probably won't have a severe allergic reaction the first time you are stung. But even if your first reaction to a sting is mild, allergic reactions can get worse with each sting. Your next reaction may be more severe or even deadly.

What causes an allergic reaction to insect stings?

An allergic reaction occurs when your immune system reacts strongly to the allergens in the sting.

A few types of stinging insects cause most allergic reactions. They are:

• Bees.
• Wasps.
• Hornets.
• Yellow jackets.
• Fire ants.

What are the symptoms?

Symptoms of an allergic reaction can range from mild to severe.

Mild reactions may cause:

• Redness, pain, and swelling around the sting.
• Itching around the sting or anywhere on your body.

Large, local reactions may cause the same symptoms as mild reactions, plus:

• Redness and swelling that affects an entire arm, leg, or large part of your body.
• Swelling that continues to increase for up to 48 hours.

A large local reaction can take up to 10 days to go away.^{footnote 1}

Severe reactions may cause:

• Hives.
• Swelling of your tongue, throat, or other body parts.
• Nausea, vomiting, or diarrhea.
• Anaphylaxis, which is a severe, life-threatening reaction that requires emergency treatment. It causes confusion, trouble breathing, and other symptoms.

How are allergies to insect stings diagnosed?

Your doctor may do a physical examination and ask you questions about your symptoms and past health. He or she also may want you to have allergy tests after you get better from the allergic reaction. Allergy tests, such as skin prick tests or blood tests, can help you find out which types of insect stings you are most allergic to.

How are they treated?

When you are stung

• For a severe reaction, such as hives, confusion, or trouble breathing:
  • If you think you are having a severe allergic reaction, give yourself an epinephrine shot in your thigh muscle.
  • Also take an oral antihistamine.
  • Then call 9-1-1 and go to the emergency room, even if you feel better.
• For a large, local reaction or a mild reaction, you can typically treat it at home.
  • Use an ice pack to reduce swelling. If you can, raise the body part where you were stung.
  • Take an over-the-counter pain reliever, such as acetaminophen (Tylenol, for example) or ibuprofen (Advil, for example).
  • Take an antihistamine to help with the itching. Read and follow the warnings on the label. And don't give antihistamines to your child unless you've checked with the doctor first.

Other treatment

If you or your child has severe reactions, your doctor may prescribe an epinephrine shot, that you keep with you or your child at all times. Teach others, such as teachers, friends, or co-workers, what to do if you're stung and how to give the shot. Also, be sure to wear a medical alert bracelet or other jewellery that lists your allergies. During an emergency, these can save your life.

You may also want to try allergy shots, called immunotherapy, to help prevent worse allergic reactions in the future.

Preventing stings

To reduce your chances of being stung:

• Stay away from places where insects nest.
• Wear shoes, long sleeves, and long pants when you are outdoors.
• Don't wear perfume or scented lotions.

If you are stung, stay as calm and quiet as you can. Then move away from the insect and leave the area, because the nest may be close by.

Remove the stinger from your skin. It may be best to scrape or flick the stinger off your skin—squeezing or gripping the stinger to pull it out may inject more venom into your wound. If you were stung in your arm or leg, lower it to slow the spread of venom. Then treat the insect sting based on the type of reaction you have.