Why Do We Itch? The Scientific Causes Are Actually Rooted in Evolution
Dermatologists break down what causes itching, plus why it feels so good to scratch.
First thing’s first: Why do we itch, anyway?
Put simply, you itch because your skin has receptors called pruriceptors (itch-sensing nerve endings) which get stimulated and, in turn, cause that itchy feeling, explains Melanie Grossman, MD, a board-certified dermatologist based in New York City. As part of the immune response, your body releases substances called histamines, triggering the itch.
There’s a deep-rooted evolutionary advantage to the itch: It’s your body’s way of letting you know ASAP that something (an allergen, a parasite like bed bugs or ticks, or a would-be intruder) is irritating your skin, the protective barrier between you and the outside world. Here are a few more common culprits:
Chemicals or medications
Sometimes, chemicals inside your body can cause itchy skin, says Dr. Grossman. For example, medications like opioids come with the common side effect of itchy skin (possibly because of shared pain-itch neurons), and illnesses like kidney and liver disease can cause itchiness due to a build-up of toxins.
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