Nearly everyone has been bitten or stung by an insect at one time or another. Whether you’ve been attacked by a mosquito, fly, bee, wasp, ant, or other bug, insect bites and stings usually cause a mild reaction. Your body reacts to venom or other proteins that insects inject into you or transfer to your body through their saliva. This can result in symptoms at the site of the bite or sting, such as:

• redness
• swelling
• pain
• itching

The severity of your symptoms can vary, depending on the type of insect that bites or stings you. Some people also develop a severe allergic reaction to insect stings or bites. Bee and wasp allergies are particularly common. A severe allergic reaction can cause:

• hives
• abdominal cramps
• nausea and vomiting
• swelling of your face, lips, or throat
• breathing problems
• shock

If you or someone you know begins to experience these symptoms shortly after being bitten or stung by an insect, call 911 or local emergency services. A severe allergic reaction that affects multiple parts of your body is called anaphylaxis. It can be life-threatening if not treated promptly.

If you’ve ever had a severe reaction to an insect bite or sting, ask your doctor about allergy testing. If you’ve been diagnosed with a severe allergy, your doctor should prescribe a medication called epinephrine. You can use a preloaded epinephrine auto-injector (e.g., EpiPen^®) to inject the medication in your outer thigh muscle. It acts quickly to raise your blood pressure, stimulate your heart, and reduce swelling of your airways. You should carry it with you at all times, especially when you’re outdoors in areas where you might encounter insects.

First aid treatment

If someone shows signs of a severe allergic reaction, help them get emergency medical attention and follow the steps in the next section. If they show no signs of a severe reaction, treat the site of the bite or sting for minor symptoms:

• If the insect’s stinger is still embedded in their skin, remove it by gently scraping a flat-edged object, such as a credit card, across their skin. Avoid using tweezers to remove the stinger, since squeezing it may release more venom.
• Wash the area of the bite with soap and water.
• Place a cold compress or ice pack on the area for about 10 minutes at a time to help reduce pain and swelling. Wrap any ice or ice packs in a clean cloth to protect their skin.
• Apply calamine lotion or a paste of baking soda and water to the area several times a day to help relieve itching and pain. Calamine lotion is a type of antihistamine cream.

Emergency treatment for a severe allergic reaction

If you suspect someone may be having a severe allergic reaction:

• Ask someone else to call 911, or local emergency services, right away. If you’re alone, contact emergency services before you provide other treatment.
• Ask the person whether they carry an epinephrine auto-injector. If they do, retrieve it for them and help them use it according to the label directions.
• Encourage them to remain calm, lie down quietly with their legs elevated, and stay still. If they start to vomit, turn them onto their side to allow the vomit to drain and prevent choking.
• If they become unconscious and stop breathing, begin CPR. Continue it until medical help arrives.

To avoid making matters worse, don’t apply a tourniquet. You should also avoid giving them anything to eat or drink.