De Quervain syndrome is inflammation of two tendons that control movement of the thumb and their tendon sheath. This results in pain at the outside of the wrist. Pain is typically increased with gripping or rotating the wrist. The thumb may also be difficult to move smoothly.Onset of symptoms is gradual.
In the image you see the modified Eichoff maneuver, commonly called the Finkelstein's test. The arrow mark indicates where the pain is worsened in de Quervain syndrome
Treatment involves avoiding activities that bring on the symptoms, pain medications such as NSAIDs, and splinting the thumb. If this is not effective steroid injections or surgery may be recommended