When a mosquito bites you, it pierces the skin using a special mouthpart (proboscis) to suck up blood. As the mosquito is feeding, it injects saliva into your skin. Your body reacts to the saliva resulting in a bump and itching.

Why do mosquito bites itch more at night?

You're not imagining it—mosquito bites do itch more at night. “Most people itch more at night because our cortisol levels (our bodies' own anti-inflammatory hormone) is higher in the morning, and also because we are less distracted as we wind down and try to fall asleep,” says Dr.

Why does it feel good to scratch a mosquito bite?

Here's how it works: when something bothers the skin, like a mosquito bite, cells release a chemical, usually histamine. That release provokes the nociceptors in the skin to send a message to the spine, which then relays the message through a bundle of nerves called the spinothalamic tract up to the brain.