One of the most difficult aspects of treating fibromyalgia (FM) is the diagnosis. This condition, which causes fatigue and widespread pain and tenderness, shares symptoms with several other diseases, particularly rheumatoid arthritis (RA).

Both fibromyalgia and rheumatoid arthritis affect women more often than men, and the symptoms vary from person to person.

Symptoms Common to Fibromyalgia and Rheumatoid Arthritis

  • joint pain and tenderness
  • fatigue
  • muscle pain
  • morning stiffness
  • reduced mobility
  • sleep problems
  • depression
  • mild fever
  • restless leg syndrome

5 Differences between Fibromyalgia and Rheumatoid Arthritis


Currently there are no diagnostic tests for fibromyalgia. Doctors diagnose the condition based on a patient's symptoms. If you have widespread pain in the four quadrants of your body for a at least three months, and pain in 11 or more of the 18 identified tender points when pressure is applied, you likely have FM.

On the other hand, there are several tests RA, including blood tests to identify markers of the disease such as rheumatoid factor and erythrocyte sedimentation rate, which measures the level of inflammation in the body.

Other tests for rheumatoid arthritis include imaging tests such as X-rays and ultrasounds, synovial fluid analysis, and motor function assessments.

Disease activity

Although fibromyalgia is frequently referred to as an autoimmune disease, it isn't. However, rheumatoid arthritis is, and occurs as a result of your body's immune system attacking itself, particularly the joints.

Also, in RA, certain chemicals in the body are released or increased that play a role in the immune system, including cytokines such as tumor necrosis factor and various interleukins.


According to the American College of Rheumatology, fibromyalgia affects about three to five million Americans. Rheumatoid arthritis, the second most common form of arthritis behind osteoarthritis, afflicts about 1.3 million Americans.

Fibromyalgia is seven times more likely to affect women than men, and rheumatoid arthritis affects women three times more than men.

Based on the greater occurrence of FM - both in the general population and among women--compared to RA, FM is seen as a bigger risk for women.

Sensory hypersensitivity

People with fibromyalgia often experience photophobia, a heightened sensitivity to light, as well as a higher sensitivity to noise. This symptom is rarely observed in RA, unless it accompanies another co-occurring disease such as lupus.

However, people with rheumatoid arthritis may experience sensitivity to sunlight if they are taking a drug such as sulfasalazine (Azulfidine®).

Sleep problems

Although both fibromyalgia and rheumatoid arthritis can disrupt sleep, researchers have identified certain sleep changes in people with fibromyalgia not found in rheumatoid arthritis.

According to the Johns Hopkins Arthritis Center, abnormal brain waveforms occur during deep sleep in people who have FM. Furthermore, the levels of growth hormone, which is predominantly produced during deep sleep, tend to be lower in people who have fibromyalgia.

Also, research shows that people with fibromyalgia report more insomnia, lack of deep and restful sleep, sleep discontentment than people with rheumatoid arthritis.