Why Do We Itch?

Scratching feels incredibly soothing because it provides relief and satisfaction, but it can also have negative effects.

In skin-related medical conditions like dermatitis, where itching is a common symptom, excessive scratching can worsen the condition. Itching too much can be both harmful and pleasurable, raising the question: Why do we itch?

According to Harvard Medical School immunologist Isaac Chiu, one possible evolutionary purpose of this preserved behavior is to remove parasites, tiny insects, or other itch-inducing materials from the skin’s surface.

A study published in Science by researchers at the University of Pittsburgh suggests that itching activates the immune system to alleviate skin inflammation and enhances defense against bacterial infections.

The researchers noted that these findings could pave the way for improved treatments for skin-related medical conditions like eczema—either by reducing inflammation or by preventing the urge to scratch.