Itchy fingertip - ideas?

[Panticus]

Hello all

I'm looking for ideas on what could be causing one of my fingertips to be constantly itchy. It's the same finger (right index) and it has been like this for years. I often end up chewing it to "scratch the itch" and eventually the skin will kind of bubble up like the attached pic shows. If I peel that off it will just be fresh skin underneath and there is no fluid. It drives me insane! It only affects that finger and I haven't noticed a pattern in terms of what makes it better or worse. I do have quite dry sensitive skin but I can't work out why only one finger is affected.

Has anyone experienced anything like this?