I have this as well, but at my right hand mostly. There could be multiple causes, diabetes is just one of them. I've just read that moving to a low-carbs diet may lead to this as well, for a week or two.
If you stay too much with a computer, or at a desk, and use your hand in a weird way, this may happen as well.
Also, if you are or you've been a heavy drinker (as I was), you may have nerve damage, and this may get slightly better only in time and with exercise.