eli5 Why do we get a red bump when bitten by an insect?

Question

eli5 Why do we get a red bump when bitten by an insect?

In: 1

Answer 1

It is our body’s reaction to the insect’s saliva. The saliva contains a chemical that our body is allergic to. When the insect bites us, it injects the saliva under our skin. Our body’s immune system reacts to the chemical and causes the bump