What should you know about MCP thumb pain?

Pain may be linked to a sprain, tendon irritation, joint inflammation, arthritis or a small fracture. Swelling, bruising, reduced pinch strength, stiffness or pain when gripping can help a clinician narrow the possibilities. Pain on the thumb side of the wrist rather than directly at the MCP joint can fit [De Quervain's Tenosynovitis](/conditions/de-quervain-tenosynovitis/), but location alone cannot confirm a diagnosis.

Reduce gripping, pinching and repetitive thumb movements for a short period, while keeping gentle motion within comfort so the joint does not become stiff. Cold wrapped in cloth may ease recent swelling. A thumb support can reduce aggravating movement, but it should not cause numbness or colour change. Arrange assessment if pain persists, follows an injury, or limits everyday tasks; a clinician may check ligaments, tendons and joint movement.

Seek urgent care after a fall or impact if the thumb looks deformed, cannot move, feels unstable, becomes numb or turns pale or blue. Prompt assessment is also needed for marked swelling, increasing redness and warmth, fever, or pain that is severe and worsening. A thumb injury can involve a ligament or fracture even when the skin is intact.

Is the pain coming from the MCP joint, a tendon or the wrist? Do I need an X-ray or another test? Should I use a splint, and which movements are safe while it settles?