Why does the mosquito bite swell or itch?

 

The female mosquito sucks the blood as much as it needs after piercing the human skin. But the problem for mosquitoes at this time is that human blood clots quite quickly.And once frozen, mosquitoes will no longer be able to eat blood.So when they pierce the blood so that they do not clot, they put some saliva in our body. That saliva juice contains some anticoagulants.  This saliva juice is made up of different proteins.It does not allow blood to clot in the area where the mosquito has bitten.This keeps the blood flow in the mouth of the mosquito.And they can eat blood comfortably.

The protein in this saliva juice does not match any protein in our body, so our immune system is activated.Then there are some chemical reactions in that place.  As a result, the area becomes swollen and itchy immediately after or after a mosquito bite.