Symptoms of de Quervain's tenosynovitis include:

• Pain near the base of your thumb
• Swelling near the base of your thumb
• Difficulty moving your thumb and wrist when you're doing something that involves grasping or pinching
• A "sticking" or "stop-and-go" sensation in your thumb when moving it

If the condition goes too long without treatment, the pain may spread further into your thumb, back into your forearm or both. Pinching, grasping and other movements of your thumb and wrist aggravate the pain.

Chronic overuse of your wrist is commonly associated with de Quervain's tenosynovitis.

Tendons are rope-like structures that attach muscle to bone. When you grip, grasp, clench, pinch or wring anything in your hand, two tendons in your wrist and lower thumb normally glide smoothly through the small tunnel that connects them to the base of the thumb. Repeating a particular motion day after day may irritate the sheath around the two tendons, causing thickening and swelling that restricts their movement.

Other causes of de Quervain's tenosynovitis include:

• Direct injury to your wrist or tendon; scar tissue can restrict movement of the tendons
• Inflammatory arthritis, such as rheumatoid arthritis

Risk factors for de Quervain's tenosynovitis include:

• Age. If you're between the ages of 30 and 50, you have a higher risk of developing de Quervain's tenosynovitis than do other age groups, including children.
• Sex. The condition is more common in women.
• Being pregnant. The condition may be associated with pregnancy.
• Baby care. Lifting your child repeatedly involves using your thumbs as leverage and may also be associated with the condition.
• Jobs or hobbies that involve repetitive hand and wrist motions. These may contribute to de Quervain's tenosynovitis.

Untreated de Quervain's tenosynovitis might make it hard to use your hand and wrist properly and limit your wrist's range of motion.