context: Anyone can sprain a wrist or fracture a bone. Usually, it heals and you forget about it. But sometimes, an injury may trigger other trouble for no apparent reason. You may feel more pain than makes sense for the injury. A hurt finger or toe, for instance, might lead to problems affecting the entire arm or leg. You might feel sharp pain from just a slight touch on your skin. Any of these reactions could be a sign of complex regional pain syndrome. That's a type of chronic pain, discomfort that lasts longer than 6 months. It's not common. But when it happens, it's best to start treatment quickly. The most likely time for complex regional pain syndrome to begin is after someone hurts a hand, foot, arm, or leg. Doctors think the condition may stem from damage to the nervous system. But they aren't sure. One theory says it may start because something goes wrong with the healing process from the original injury. The effects of complex regional pain syndrome can grow more serious with time. So the sooner you find out if you have it, the better. The condition's main sign is intense pain that affects you all the time. If you have it, you might see or feel some of these in a hand, foot, arm, or leg: Constant burning or throbbing pain Swelling Sensitivity to touch or cold Changes in skin temperature between sweaty and cold Skin that becomes white, mottled, red, or blue Skin that turns thin or shiny Joint stiffness or swelling Nails or hair growing faster than normal Muscle spasms or weakness Difference in temperature between the affected limb and the opposite one ( One may sweat more than the other.) Pain in the opposite limb from the one that was injured Complex regional pain syndrome usually goes through three stages. As it does the symptoms get more severe: Up to three months: You feel burning pain, and the affected area is more sensitive to touch. Those are the most common early symptoms. Swelling and joint stiffness usually start next. Three months to a year: Swelling is more lasting, and wrinkles in the skin go away. Pain spreads, and joints get stiffer. A year or more: Skin becomes pale, stretched, and shiny. Pain may lessen. Stiffness may mean that the affected limb won't ever move as well as it used to. Even though complex regional pain syndrome most often appears after an injury, that isn't the only cause. It also can be triggered by an infection, heart attack, stroke, cancer, neck problems, or pressure on a nerve. The condition is a rare disorder. It mainly shows up in people from 20 to 35 years old. And it affects women more often than men. Seniors rarely get it, and very few children do. Almost no one younger than age 5 gets it. Doctors sometimes divide the disease into two categories: Type 1 happens after an injury that didn't directly affect a nerve. Type 2 follows an injury that harmed a nerve. Either way, the symptoms are the same. No single test will show whether you have complex regional pain syndrome. So your doctor will probably start with your symptoms and other clues, such as whether you've had an injury that could have triggered the condition. You may get tests that can rule out other things, such as arthritis. X-rays and other tests of your bones may shed light on the trouble. Your doctor may also want to see whether the ailing limb is warmer than the opposite one or sweats a different amount. Unfortunately, some people may say that you're exaggerating the discomfort. But if you're in pain, listen to what your body is telling you and ask for help. Complex regional pain syndrome is a real illness. You aren't imagining it. Doctors haven't found a cure. So they focus on relieving the pain and other symptoms. The options may include: Pain killers ranging from over-the-counter aspirin to more powerful medicines that you can only get with a prescription. Anti-swelling medicine. Anesthetic creams and patches that numb the affected area. Physical therapy to improve blood circulation and make the injured arm or leg more flexible. Spinal cord stimulation by a battery-powered device put in during surgery. Surgery that destroys some of the nerves. Doctors disagree about whether this helps. If your treatment starts within a few months after the symptoms appear, there's a good chance your pain will ease up or go away. Children and teenagers generally have the best luck. As you work on getting better, these steps may help: Keep up your usual daily routine as much as you can. Get plenty of rest. Don't try to do more than your strength can handle. Look to your family and friends for support. Speaking of family and friends, some of them may have a hard time believing how much pain you're in. That's a common problem with this illness. Share with them information about complex regional pain syndrome so they can better understand what you're dealing with. Long-term pain can take a toll on your mind and emotions. Being depressed or other psychological troubles can make it harder to recover. So tell your doctor. Therapy, lifestyle changes, and medication may help. Your doctor should also be able to connect you with other health professionals who can help. They might teach you relaxation or meditation techniques, for instance. And in support groups, you can draw from other people's strength and share yours with them.