Mosquito bites: What is a normal skin reaction?

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Mosquito bites: What is a normal skin reaction?


When a mosquito bites me, I get big, nickel-sized welts. Is this normal?



A "normal" reaction to a mosquito bite can vary. Some people will have only a small area of redness, swelling and itching that typically goes away within 24 hours. Others may have a larger area of itching — sometimes the size of a grapefruit in highly sensitive individuals — that can last for several days.

In some cases, hypersensitivity to mosquito bites may be associated with an underlying medical condition, such as chronic lymphocytic lymphoma or certain viral infections, such as Epstein-Barr virus. However, this is uncommon.

Rarely, an individual may have a serious reaction to mosquito bites, which results in swelling in the throat, hives and wheezing. This life-threatening condition (anaphylaxis) requires immediate medical attention.

If you're sensitive to mosquito bites, the best advice is to avoid getting bitten. Follow these common-sense precautions:

  • Avoid areas, such as marshes, where mosquito activity is highest.
  • Avoid going outside when mosquitoes are most active, such as at dusk and dawn and after rain.
  • Wear protective clothing when outside.
  • Use insect repellent.

To relieve the itching of a bite, apply a lotion containing calamine. If you have a large local reaction, consider taking an over-the-counter antihistamine, such as diphenhydramine (Benadryl) to see if it helps. Consult your doctor if you're concerned about the severity of your reaction.

Last Updated: 05/25/2006
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