Tingling in thumb and little finger base

For past two days, my son,his age is 25, is having tingling sensation in BOTH HANDS, on the base of small finger and thumb of right and left hands, Also on wrist, mostly whenever when he is typing something. There is no numbness or loss of strength, and movement of hands are fine. He doesn't use mobile phone for much for typing but past couple of weeks due to some work he is been using it continuously. After this he is having this problems. He had a wrist hairline facture, 5 year ago. When he moves his fingers of both fingers randomly in very fast Pace, he doesn't feel any tingling. It only while using his phone, 70% of tingling is at base of thumb fingers of both hand, and wrist of both hand. He doesn't have diabetes or any underlying condition.