Biology Fun Fact

Why Do We Itch?

Natchya Tiwari

Itching can be triggered by all sorts of things, including allergic reactions, dryness or maybe some diseases. There are some mysterious ones also that come for no reason at all or just from thinking about itching, for example, you are scratching yourself somewhere right now, aren’t you?

Let’s talk about one of the most common sources, bug bites. When a mosquito bites us, it releases a compound into our bodies called an anticoagulant that prevents our blood from clotting. It depends upon the compounds that we are allergic to. It triggers the release of histamine, a chemical that makes our capillary swell. It enables the blood-flow that makes the body’s immunity system response to this threat. It causes the swelling. Histamine also activates the nerves involved in itching, that is why the bug bites make us scratch.

There’s a molecule that the nerves produce. It is called natriuretic polypeptide B, which triggers a signal that is carried up to the spinal cord and then to the brain, where it creates the feeling of itching. But the itchy sensations aren’t fully understood yet.