Hi Paul,
Paraesthesia and/or nerve entrapments (i.e. carpal tunnel syndrome) are recognised symptoms of hypothyroidism ('under-active') as far as I'm aware. So that does fit with your current thyroid status...
Hopefully, when you reach the correct dose of thyroxine, this tingling will rectify itself
You've said you've ruled out carpal tunnel, but I suppose it could still be that?
Do the pins and needles occur in specific fingers more than others? For example your thumb and index finger more? Symptoms of CTS are also worse at night - is this something you noticed? But yes, you are right, symptoms of CTS are often worse after using the affected hand, so this wouldn't fit with you using it at work and not getting the same sensation.
Some tests you could try for CTS:
http://www.youtube.com/watch?v=yQ1GE4RiJLw
(Sorry for the crude video - it's easier than trying to describe).
If you are worried that you have CTS, then I'd get to your GP
Of course, I can't say for definite, but I suspect the pins and needles are a symptom of being hypothyroid and that it will get better with normalisation of your thyroid hormone levels with the correct dose of thyroxine.
One other thing that springs to mind that can cause pins and needles sensation is a low calcium level, so maybe this is another thing to check out too?
I hope this helps, and I hope you feel better soon! Good luck
