Wrist tendonitis, also known as tendinitis, is inflammation in the tendons that connect the muscles of the forearm to bones in the wrist and fingers. It is typically caused by repetitive stress on the tendons in the wrist, which can irritate the tendon sheath, leading to inflammation and enlargement. This makes it harder for the tendons to glide smoothly through the sheath, causing compression on the tendon and making wrist and finger movements painful. Wrist tendonitis can also be caused by injury, certain conditions such as arthritis or diabetes, ageing, weak wrists, or poor joint and bone structure.

Symptoms of wrist tendonitis may include difficulty performing certain movements, such as opening jars or turning doorknobs, or lifting pets, babies, or small children, stiffness, "catching" or a popping sensation when moving your wrist or fingers, swelling around your wrist or the bases of your fingers, and wrist pain, especially along the side of the wrist near the thumb or pinkie finger.

Wrist tendonitis can be diagnosed by a hand/wrist specialist, who will examine the wrist and ask about symptoms. Treatment options include immobilizing the wrist using a splint or cast to allow the tendon to rest, reducing inflammation by applying an ice pack, taking anti-inflammatories to decrease the inflammatory response, and cortisone injections into the tendon to reduce pain and inflammation. Occupational therapy, wrist bracing, and surgery may also be recommended depending on the type and extent of tendonitis.