It itches when you clean it. But some yams itch when you eat it
The fresher a yam the less the itch, the older the yam more the itch.
There is something acidic in yam, esply close to its skin, that causes the itch.
You should wash your hands with cold water when it starts itching. Some people can also develop allergy to the itch which can result in red rashes. So consult a doc.
Yam should be boiled and drained well to remove the itch causing substance.
When men clean/ cut yam they dont develop itches. Only women do.
I am not copy pasting this from anywhere. I read a lot about yam today and this is a summary.