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Chronic Fatigue Syndrome Health Center

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Other Conditions With Symptoms Similar to Chronic Fatigue Syndrome

Fatigue can be a symptom of hundreds of medical conditions. All other possible causes of fatigue will be ruled out before chronic fatigue syndrome (CFS) is diagnosed. Exams and tests are used to rule out the most likely causes of fatigue, depending on the person's medical history and symptoms.

Chronic, persistent fatigue may be a symptom of various conditions, including:

Recommended Related to Chronic Fatigue Syndrome

Chronic Fatigue Syndrome

Important It is possible that the main title of the report Chronic Fatigue Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

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  • Fibromyalgia. Although fibromyalgia and CFS can have similar symptoms, people who have fibromyalgia tend to have more muscle pain and more specific tender points than people who have CFS. In contrast, the main symptom of CFS is overwhelming fatigue. Also, fibromyalgia is much more common than chronic fatigue syndrome, affecting as many as 5 million people in the United States.1
  • Lyme disease.
  • Depression or anxiety.
  • Infectious mononucleosis (mono).
  • Multiple sclerosis (MS) or myasthenia gravis.
  • Anemia.
  • Diabetes.
  • Insomnia.
  • Sleep apnea.
  • Hypothyroidism.
  • Lupus.
  • Rheumatoid arthritis.
  • Infectious diseases, such as hepatitis, syphilis, or human immunodeficiency virus (HIV) infection.
  • Certain types of cancer (lymphoma, leukemia).
  • Neurasthenia, or nervous exhaustion, a disease marked by intense nervous irritability and weakness.
  • Multiple chemical sensitivity disorder, a controversial diagnosis of an allergy-like sensitivity to an unusually broad range and number of substances. This condition has not been subjected to rigorous scientific scrutiny, and there is considerable doubt as to whether it actually exists.

Other possible causes of fatigue include:

  • Stress.
  • Medicine side effects, or medicines changed or added too quickly.
  • Alcohol or drug abuse.
  • Too little exercise or excessive exercise (overtraining).


  1. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) (2009). Questions and Answers About Fibromyalgia. Available online:

By Healthwise Staff
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Nancy Greenwald, MD - Physical Medicine and Rehabilitation
Last Revised April 22, 2011

WebMD Medical Reference from Healthwise

Last Updated: April 22, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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