What Is Fibromyalgia?

Fibromyalgia syndrome is a common and chronic disorder characterized by widespread pain, diffuse tenderness, and a number of other symptoms. The word “fibromyalgia” comes from the Latin term for fibrous tissue (fibro) and the Greek ones for muscle (myo) and pain (algia).

Although fibromyalgia is often considered an arthritis-related condition, it is not truly a form of arthritis (a disease of the joints) because it does not cause inflammation or damage to the joints, muscles, or other tissues. Like arthritis, however, fibromyalgia can cause significant pain and fatigue, and it can interfere with a person’s ability to carry on daily activities. Also like arthritis, fibromyalgia is considered a rheumatic condition, a medical condition that impairs the joints and/or soft tissues and causes chronic pain.

Who Gets Fibromyalgia?

Scientists estimate that fibromyalgia affects 5 million Americans age 18 or older. For unknown reasons, between 80 and 90 percent of those diagnosed with fibromyalgia are women; however, men and children also can be affected. Most people are diagnosed during middle age, although the symptoms often become present earlier in life.

People with certain rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus (commonly called lupus), or ankylosing spondylitis (spinal arthritis) may be more likely to have fibromyalgia, too.

Several studies indicate that women who have a family member with fibromyalgia are more likely to have fibromyalgia themselves, but the exact reason for this—whether it is heredity, shared environmental factors, or both—is unknown. Researchers are trying to determine whether variations in certain genes cause some people to be more sensitive to stimuli, which lead to pain syndromes. (See “What Research Is Being Conducted on Fibromyalgia?”)

What Causes Fibromyalgia?

The causes of fibromyalgia are unknown, but there are probably a number of factors involved. Many people associate the development of fibromyalgia with a physically or emotionally stressful or traumatic event, such as an automobile accident. Some connect it to repetitive injuries. Others link it to an illness. For others, fibromyalgia seems to occur spontaneously.

Many researchers are examining other causes, including problems with how the central nervous system (the brain and spinal cord) processes pain.

Some scientists speculate that a person’s genes may regulate the way his or her body processes painful stimuli. According to this theory, people with fibromyalgia may have a gene or genes that cause them to react strongly to stimuli that most people would not perceive as painful. There have already been several genes identified that occur more commonly in fibromyalgia patients, and NIAMS-supported researchers are currently looking at other possibilities.

How is fibromyalgia diagnosed?

People with fibromyalgia often see many doctors before being diagnosed. One reason for this may be that pain and fatigue, the main symptoms of fibromyalgia, also are symptoms of many other conditions. Therefore, doctors often must rule out other possible causes of these symptoms before diagnosing fibromyalgia. Fibromyalgia cannot be found by a lab test.

A doctor who knows about fibromyalgia, however, can make a diagnosis based upon two criteria:

A history of widespread pain lasting more than 3 months. Pain must be present in both the right and left sides of the body as well as above and below the waist.
Presence of tender points. The body has 18 sites that are possible tender points. For fibromyalgia diagnosis a person must have 11 or more tender points. For a point to be “tender,” the patient must feel pain when pressure is put on the site. People who have fibromyalgia may feel pain at other sites, too, but those 18 sites on the body are used for diagnosis.

Your doctor may try to rule out other causes of your pain and fatigue. Testing for some of these things may make sense to you. For instance, you may find it reasonable that your doctor wants to rule out rheumatoid arthritis, since that disease also causes pain. Testing for other conditions — such as lupus, multiple sclerosis, or sleep apnea — may make less sense to you. But fibromyalgia can mimic or even overlap many other conditions. Talk with your doctor. He or she can help you understand what each test is for and how each test is part of making a final diagnosis.