De Quervain's disease is a term used to describe a painful disorder affecting the tendons at the base of the thumb. This is one of the most common kinds of tendon lining inflammatory diseases or tenosynovitis. These tendons are encased in sheaths, or sleeves, through which the tendons slide. The inner wall of the sheaths contains cells that produce a slippery fluid to lubricate the tendons. With repetitive or excessive movements such as hand twisting and forceful gripping, the lubrication system may malfunction. Failure of the lubricating system allows friction to develop between the tendons of the thumb and their common sheath. The repetitive friction accounts for the abnormal thickening and the constriction of the sheath which interferes with the smooth gliding motion of the tendons.

The patient experiences pain when moving the thumb away from the hand and has difficulties with activities requiring a firm grip and twisting of the hand. The pain occurs at the base of the thumb and the radial side (same side as the thumb) of the forearm.

Medical management of De Quervain's disease consists mainly of splinting the thumb and wrist to avoid those movements that caused the disorder. Physicians may prescribe anti-inflammatory drugs to reduce the pain and inflammation. The majority of patients with De Quervain's disease respond to medical management but in some cases surgical release of the affected tendons may be necessary.

The prevention of De Quervain's disease consists of avoiding excessive movements such as hand and wrist twisting and forceful gripping. Thumb pressure in pushing controls or while typing should also be avoided.