Why does it eich when a muscetio bites you?

When a mosquito bites you, it injects saliva containing anticoagulants to prevent your blood from clotting while it feeds. This saliva triggers an immune response, causing inflammation and the release of histamines, which results in the itching sensation. The body's reaction to the saliva is what makes the bite feel itchy and uncomfortable. Additionally, scratching the bite can further irritate the skin and exacerbate the itching.