This is called De Quervain's disease. This is a sort of entrapment of the pulley or tendon going to the thumb; responsible for the outward movement of it. It is diagnosed clinically basing mainly on two tests. First there is pain on pressure over the outer side of wrist where the bone called radius ends. In the second test patient gets pain when asked to clinch the fist with thumb pressing all other fingers, and patient asked to deviate the wrist away from the side of pain. That puts unusual stress and strain on the muscles of outer side of the forearm, and patient gets pain.
Treatment comprises of rest to the wrist, moist heat application and prescription of simple analgesics. If, no response is seen, local infiltration of steroid (Triamcinolone or methylprednisolone) contemplated. This is given after blood sugar estimation. Usually that cures many, but sometimes, a second or third injection may be required in a few patients. The side effects could be; discoloration of skin at the site of injection, local pain and infection.
The last option is surgery; intended to release the entrapped tendon. Here care is taken not to damage the superficial small nerves to skin and minute blood vessels to the finger. The limb is immobilized for some time, antibiotic and analgesics are prescribed for a few days. Hand is kept elevated to reduce pain. Early physiotherapy is instituted after removal of sutures.
And, the De Quervain's disease is gone.