Pain on the back of the thumb: what to check

The most informative details are whether pain sits near the wrist or a thumb joint, whether there was a fall, and whether gripping, pinching or moving the thumb brings it on.

Tenderness along the thumb side of the wrist that worsens with lifting, gripping or thumb movement can occur when tendons and their covering become irritated. De Quervain's tenosynovitis commonly presents with pain and tenderness near the base of the thumb on the wrist side, sometimes with swelling or a catching sensation.

Pain centred over a knuckle may instead come from the joint or its supporting ligament. After a fall, direct blow or forced bend, swelling, bruising and reduced pinch strength raise concern for a sprain, dislocation or fracture.

Temporarily reduce repeated pinching, scrolling, heavy gripping and lifting that reproduces symptoms. Keep the thumb moving gently within a comfortable range unless an injury has made it unstable or markedly swollen. A wrapped cold pack can help after a recent flare, with a barrier protecting the skin.

A suitable splint may limit an aggravating motion, but fit and duration matter because unnecessary immobilisation can cause stiffness. If pain continues, a clinician can assess tendon glide, joint stability, sensation and grip, then tailor exercises or arrange imaging when injury is suspected.

Seek urgent care after trauma if the thumb looks misshapen, feels unstable, becomes numb, turns pale or blue, or cannot move normally. A cut, bite or puncture followed by spreading redness, heat, pus, fever or rapidly increasing swelling also needs prompt medical attention.

Arrange a routine assessment when pain interferes with grip, repeatedly returns, causes clicking or locking, or fails to improve after modifying the provoking tasks.

Ask whether the tenderness follows a tendon or sits within a joint, whether ligament stability is normal, and whether a splint would help. Clarify which hand tasks to modify, which exercises are appropriate and what finding would justify an X-ray or another test.