Pain and swelling between the thumb and index finger: what to know

The web space contains small muscles, connective tissues and structures that help the thumb pinch and spread. Repeated lifting, gripping, texting or caring for a baby can overload the thumb side of the hand. De Quervain's tenosynovitis affects tendons on the thumb side of the wrist and may make thumb movement, grasping or lifting painful; discomfort can be felt toward the base of the thumb and nearby web space. A fall, forceful pull or jammed thumb can instead cause a sprain. Bruising, a clicking sensation, reduced grip or pain with a specific movement helps a clinician separate these possibilities.

Rest from forceful pinching and repetitive gripping, while moving the fingers gently within comfort. A cold pack wrapped in cloth may reduce early swelling. Keep the hand elevated when resting and avoid tight jewellery. A thumb-supporting splint may reduce tendon motion, but it should not cause numbness or colour change. A clinician or hand therapist can check technique, range of motion and grip before recommending exercises.

Get prompt assessment after a significant injury, visible deformity, inability to move the thumb, major loss of grip, increasing redness or warmth, or numbness. Seek urgent care if the thumb or hand becomes pale, blue or unusually cold. Arrange a review if swelling does not settle, pain interferes with sleep, or ordinary grasping remains difficult.

Ask which tendon or joint is involved, whether a splint is suitable, and which movements should be limited. Ask how to protect the thumb during work and when strengthening can safely begin.