Why do we get swelling with insect bites?

If you have an insect bite from a mosquito, fly, bee, or wasp, it will cause temporary pain, itching, swelling, and redness. You’ll notice these changes at the time of the bite or sting. Symptoms may increase over hours to days, depending on the insect. The local inflammatory changes are a result of a reaction to the venom or other substances injected into the skin during the bite or sting.

What should I do if I have an insect bite?

Usually, the skin reaction will gradually subside on its own. You can try an over the counter  antihistamine such as loratadine (Claritin) or cetirizine (Zyrtec). Diphenhydramine (Benadryl) can also be used, but will cause sedation in most people. If stung, try to remove the stinger from the skin. A steroid cream can be prescribed, if necessary, to be used to decrease inflammation and itching.

When should I seek help for an insect bite or sting?

Seek medical attention if you have:
• Difficulty swallowing or breathing
• Chest tightness
• Widespread hives
• Swelling of the lips, tongue or throat
• Nausea, vomiting, diarrhea
• Fatigue, significant increase