Reflex sympathetic dystrophy syndrome (RSDS) is characterized by pain and swelling, usually of one hand or foot; sometimes, however, it affects a knee, hip or one or two fingers or toes.

In at least 75% of all cases RSDS can be traced to a precipitating event: infection, trauma, injury, heart attack, or stroke. Some cases may be related to repetitive strain injury, such as carpal tunnel syndrome.

Certain drugs may also cause pain and swelling in the joints; these include barbiturates, anti-tuberculosis drugs, or cyclosporine, an anti-inflammatory agent administered to patients undergoing kidney transplants.

RSDS occurs most often in people over the age of 50. Although distinct stages may be difficult to identify in some individuals, and not everyone goes through each stage.

RSDS Typically Progresses in Three Stages:

1. First – third month after a precipitating event, the hand or foot will begin to swell. Intense pain may be felt – usually a burning throbbing or aching sensation. If recovering from an injury or operation, lingering pain may be experienced. Joints feel tender. Even the lightest touch or the slightest movement can cause pain. Changes may occur in the temperature and color of skin, along with sweating. Other symptoms may include rapid hair and nail growth. At this stage, the condition is more likely to be identified as rheumatoid arthritis. Redness and swelling may also suggest infectious or inflammatory arthritis. However, if the condition is properly diagnosed at this point, treatment may interrupts its progress.
2. Within three – six months, the skin of hand or foot becomes shiny, thin, and cool. Pain can be triggered by changes in temperature or by other light stimulation, a touch, a breeze, or air conditioning. The skin becomes cool, swollen, pale and waxy, and the nails brittle. Pain may spread towards the center of the body, from the foot to the hip, for example, or from the hand to the shoulder. Often the spreading pain affects the muscles, producing painful spasms.
3. In another 3 to 6 months, the skin becomes drawn, dry and shriveled. Permanent changes may result at this point. The pain may be severe, although some people feel less pain. Surrounding muscles and other tissues can atrophy and contract. Joint movement becomes greatly restricted.

There are neither medications nor surgical remedies to correct the condition or eliminate the pain of RSDS. The earlier the condition is diagnosed, the better the prognosis. However, the overall response rate to treatment is poor with over 50% of patients reporting significant pain and sometimes disability years later.