10 Conditions Often Mistaken for Fibromyalgia

by Karen Lee Richards Patient Advocate

It's not unusual for fibromyalgia to be misdiagnosed as another condition and vice versa, since many symptoms of fibromyalgia are very similar to those of other illnesses. Only recently has a test been developed, and many doctors are still not aware of it. Also, people living with fibromyalgia will often have one or more overlapping conditions, which further complicates diagnosis. Here are 10 conditions commonly mistaken for fibromyalgia.

Man fatigued during work.

Chronic fatigue syndrome

Chronic fatigue syndrome (also called ME/CFS) is the condition that is probably most often confused with fibromyalgia. That's understandable since an estimated 70 percent of people who have one also have the other. The symptoms of each are remarkably similar. So much so that some experts believe fibromyalgia and chronic fatigue syndrome are slightly different expressions of the same basic illness.

Woman getting a thyroid exam from a doctor.


Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone. This is another condition that shares a lot of fibromyalgia’s symptomatology. Some symptoms common to both include joint or muscle pain, fatigue, sensitivity to cold, constipation, depression, and weight gain.

Woman at work wincing from headache and stiff neck.


Lupus is an autoimmune disease, meaning the immune system of a person with lupus will attack normal cells as if they were outside invaders. This can cause inflammation, tissue damage, and pain throughout body, which feels very much like the widespread body pain of fibromyalgia. Although there is no single test that will identify lupus 100 percent of the time, there are lab tests that can help your doctor determine whether you may have lupus.

Joint pain.


Osteoarthritis is generally caused by age-related deterioration of the cartilage in joints, which can lead to tissue and bone damage. Symptoms similar to fibromyalgia include joint pain and morning stiffness. A physical exam and a variety of diagnostic tests may be helpful in making a diagnosis of osteoarthritis.

Doctor examining a woman's knee.

Rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease that causes inflammation and destroys the lining of the joints. Symptoms rheumatoid arthritis may have in common with fibromyalgia include pain, fatigue, sleep disturbances, depression, and anxiety. Rheumatoid arthritis can be difficult to diagnose since blood work and X-rays may show normal results for many months after the onset of joint pain.


Multiple sclerosis

Multiple sclerosis is a disease in which the body's immune system eats away at the myelin sheath that covers and protects the nerves. This interferes with the brain's ability to communicate with the rest of the body. Symptoms fibromyalgia and multiple sclerosis have in common may include pain, fatigue, numbness, tingling, cognitive impairments, poor coordination, and blurred vision.

Depressed man.


For years people with fibromyalgia have been told by doctors that they're "just depressed." Although depression is often listed as a symptom of fibromyalgia, clinical depression is actually a separate and distinct condition that sometimes overlaps with fibromyalgia. Some common symptomatology includes pain, fatigue, and difficulty with memory and concentration.

Tick on a finger.

Lyme disease

Lyme disease is caused by bacteria spread from the bite of a deer tick. Chronic lyme disease is often misdiagnosed as fibromyalgia. Why? Many of the symptoms of Lyme disease mimic those of fibromyalgia, such as muscle and joint pain, fatigue, headaches, cognitive impairment, and digestive disorders. Also, Lyme disease can be very difficult to accurately diagnose since many of the blood test used are unreliable.

Man sleeping on the couch.

Sleep apnea

Sleep apnea is a disorder in which breathing repeatedly stops and starts while sleeping. The result can be many of the same symptoms as fibromyalgia including unrefreshing sleep, fatigue, achiness, headaches, and cognitive problems. If a fibromyalgia patient is found to have sleep apnea, often treating the sleep apnea will lead to significant improvement of other symptoms as well.

Older man in pain.

Polymyaglia rheumatica

Polymyalgia rheumatica is form of arthritis that causes muscle pain in multiple parts of the body and rarely occurs in anyone under 50. It shares some of fibromyalgia's most prominent symptoms — pain, achiness, morning stiffness, and fatigue.

Karen Lee Richards
Meet Our Writer
Karen Lee Richards

Karen is the co-founder of the National Fibromyalgia Association. She writes for HealthCentral as a patient expert for Pain Management.