What is the function of itching?

Mosquito bites – so small, yet so maddening. You know scratching makes it worse, but it’s almost impossible to resist. But is there actually a function to that itching in the first place?

Warning signal

Itching, however annoying, does actually serve a purpose. ‘Itching serves as a warning mechanism,’ says Bing Thio, a dermatologist at Erasmus University Medical Centre in Rotterdam. ‘It’s your body’s way of saying something is not right with your skin.’

Whether it’s a mosquito bite, a tick attaching itself to the back of your knee or head lice, that itchy sensation is impossible to ignore. The same uncomfortable signal flares up when your skin reacts to the chemicals released by stinging nettles or in harsh detergents.

Mostly useful

When something irritates your skin, special defender cells spring into action, releasing histamine. This chemical acts like a messenger, alerting your immune system that something is wrong and it’s time to respond.

Histamine also triggers the itch sensors in our skin. These send a signal straight to the brain, which responds with a simple command: scratch or rub! It’s a clever trick our body uses to get rid of whatever is causing trouble – like an insect or an irritant. This is mostly very useful.

Ever noticed how wounds start to itch as they heal? That’s no accident. ‘Your body releases histamine and other substances that cause the itching during the repair process,’ Thio explains. ‘The itch helps you stay aware of the wound. And sometimes, scratching off the scab can actually speed up healing.’

Distract yourself

A bit of scratching can feel satisfying. But go too far, and you’re doing more harm than good. Breaking the skin can actually make the itching worse by ramping up your immune response.

Thio suggests that the best way to deal with an itch is to distract yourself, shifting your focus to another sensation. Try a cold shower, a gentle pinch or press a cross into a mosquito bite with your fingernail.

Answered by Judith Neimeijer