I've recently had my ears pierced, and the holes are sometimes quite itchy. How come? I've heard it's because it's healing, but what exactly makes it itch?



Good question and yes the itch is caused by the healing process. This may come as a surprise to many people reading this, but we know very little about itch as compared to pain. We are not sure if the same nerves perform both functions and which receptors mediate pain (other than the histamine system which is well known in terms of insect bites). Recent work has started to look at this but the field is still in its infancy.

To try and answer your question as best I can - as the skin/wound heals it releases many factors as a result of injury and the healing process which together cause itch, as the healing process is complete the levels of these (largely unknown) factors go back to normal and the itch stops.

What Dr. Wynick said was true when he wrote it, but since then we have learned that pain and itch receptors are controlled by separate nerves.

Actually no! The latest data (and this is a rapidly evolving field) demonstrates that C-fibre nociceptors are also important for itch, though in addition some subclasses of A-fibres are also needed for the full response. Also to note all of the current studies have been done in rodents, we do not know yet whether these new findings will be applicable to man, though the assumption is yes.