Why Do Wounds Itch as they Heal?
September 19, 2017 8:39 AM   Subscribe

It seems like especially small wounds (like a scrape) can drive me bonkers with itching as they heal. I'm curious to know why wounds itch as they heal?
posted by summerstorm to Health & Fitness (5 answers total) 1 user marked this as a favorite
Best answer: The Naked Scientists have a pretty good lay person description, let us know if you want something with more biochem/biophysics.

Basically it's a combination of mechanical stress and chemical signals.
posted by SaltySalticid at 8:55 AM on September 19, 2017 [3 favorites]

Histamine. Your body releases it at the wound site as part of the healing process and it mediates itching in humans.
posted by Talez at 11:24 AM on September 19, 2017

Also, itch is sort of a mild form of pain, so it's sort of the dull ache of superficial injury...
posted by acm at 12:54 PM on September 19, 2017

I think of it as nerve endings sparking as they knit back together.
posted by rhizome at 4:03 PM on September 19, 2017

Yes, "itch" receptors and brain signals are quite similar to "pain" receptors and signals. This is part of the reason why withdrawal from strong painkillers like morphine/heroin is itchy. This is also why scratching (i.e. inflicting pain on an area of skin) relieves an itch. (But don't scratch a scab!) There are also some fun syndromes called neuropathic itch (i.e. nerve-damage itch) which I can diagnose and treat but don't even pretend to understand. If you really want to get wild, remember that pain and temperature also travel along the same fibers and are processed in similar ways (hence why opioid withdrawal makes you shiver, and why ice helps lessen pain). So, itch, pain, and temp are basically all co-opting each other's receptors and nerve fibers like a bunch of evolutionary squatters.
posted by basalganglia at 4:08 PM on September 19, 2017 [4 favorites]

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