Why do mosquito bites itch?

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Jason Daley

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Why do mosquito bites itch?
Actually, it’s half your fault. When a bloodsucker plunges its proboscis into your flesh, it injects anticoagulants that make for faster slurping. These stimulate your immune system to release histamines, organic molecules that open blood vessels, allowing white blood cells to rush in and clean up the affected area. But the histamines also cause that irritating tickle. “Itching is your body telling you something bad has happened,” explains Gregory Lanzaro, director of the University of California Mosquito Research Program. Scratching, while momentarily euphoric, will likely irritate the area, causing more immune-system responses, leading to more itching. The only true cures: cortisone cream and time.

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