Eosinophilia Myalgia Syndrome

Eosinophilia Myalgia Syndrome

National Organization for Rare Disorders, Inc.


It is possible that the main title of the report Eosinophilia Myalgia 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.


  • EMS
  • eosinophilia myalgia
  • eosinophilic myalgia
  • L-tryptophan disease
  • tryptophan disease
  • tryptophan syndrome
  • toxic oil syndrome

Disorder Subdivisions

  • None

General Discussion

Eosinophilia myalgia syndrome (EMS) is associated with the ingestion of contaminated L-tryptophan, a dietary supplement often sold in health food stores. The contaminant remains unknown. It is a disease of abrupt onset causing severe, disabling, chronic muscle pain, skin symptoms and other neurotoxic reactions . Diagnosis is not easy and depends on finding unusually high levels of eosinophils (circulating white blood cells) over a period of at least six months.


Eosinophilia myalgia syndrome may make its presence known only weeks, months, or even years after the original period of consumption of L-tryptophan. L-tryptophan is an essential amino acid present in most foods. The disorder is characterized by large amounts of eosinophils (white blood cells) in the blood. The primary symptom is severe muscle pain and weakness. There may also be associated ulcers of the mouth or other mucous membranes. Sore throat, difficulty breathing (dyspnea), swollen liver and abdomen, abdominal pain, and fever may also be present.

Skin abnormalities resembling scleroderma, including swelling and tightening of the skin, painful itching, and edema, along with peau d'orange skin of the legs, may also occur. The skin symptoms usually start in the extremities (usually the legs) with the upper body becoming involved later if at all.


Eosinophilia myalgia syndrome may be caused by the ingestion of some lots of oral L-tryptophan. Tryptophan is an essential amino acid present in very small quantities in most foods. However, the amounts ingested by patients with eosinophilia myalgia syndrome are over and above the amounts occurring naturally in food. The drug was formerly available at health food stores without prescription as a dietary supplement. Although there was no proof of effectiveness, many patients used it to treat depression, premenstrual syndrome and insomnia. During 1990 the FDA removed tryptophan from the shelves of stores and it can no longer be purchased in this country. Scientists are still trying to determine whether the tryptophan itself causes predisposed persons to manufacture neurotoxins that cause eosinophilia myalgia syndrome symptoms, or whether the tryptophan is in some way contaminated in the manufacturing process.

Scientists now believe they can confirm that L-tryptophan itself causes symptoms of EMS in patients who use the product. Further studies have shown that L-tryptophan contaminated with 1-1-ethylidenebis (ETB) causes more severe problems in people than regular L-tryptophan; still, L-tryptophan alone can cause EMS.

Affected Populations

EMS seems to affect males and females in equal numbers. The Centers of Disease Control states that as of February, 1990, 1269 cases were reported to them. Some patients have died.

Standard Therapies

Treatment of EMS consists of high doses of glucocorticoids (hydrocortisone) to reduce the amount of circulating eosinophils. This treatment, however, does not usually improve the other symptoms.

Investigational Therapies

Research on EMS is ongoing. For more information about investigational therapies contact the Centers for Disease Control listed below.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:




Puszczewicz M, Zimmermann-Górska I, Pietrzak-Kaczmarek H, Lazowski S. Diagnostic problems in eosinophilic fasciitis. Pol Arch Med Wewn. 2006 Aug;116(2):777-80.

Solomon J, Schwarz M. Drug-, toxin-, and radiation therapy-induced eosinophilic pneumonia. Semin Respir Crit Care Med. 2006 Apr;27(2):192-7.

Eosinophilic Myopathic Syndromes. M. C. Pickering et al., Current Opin Rheumatol. (Nov 1998, 10 (6)). Pp. 504-10.

Neurologic, Mr Imaging and Mr Spectroscopic Findings in Eosinophilia Myalgia Syndrome. L. J. Haseler et al., AJNR Am J Neuroradiol. (Oct 1998, 19 (9)). Pp. 1687-94.

Pain, Fatigue, and Sleep in Eosinophilia-Myalgia Syndrome: Relationship to Neuropsychological Performance. D. A. Pollina et al., J Neuropsychiatry Clin Neurosci. (Summer 1998, 10 (3)). Pp. 338-42.

Structural Characterization of Contaminants Found in Commercial Preparations of Melatonin: Similarities to Case-Related Compounds from L-Tryptophan Associated with Eosinophilia-Myalgia Syndrome. B. L. Williamson et al., Chem Res Toxicol. (Mar 1998, 11 (3)). Pp. 234-40.

Association of the Eosinophilia-Myalgia Syndrome with the Ingestion of Tryptophan. P. A. Hertzman et al.; New Eng J Med (Mar 29 1990; 322(13)). Pp. 869-73.

Scleroderma, Fasciitis and Eosinophilia Associated with the Ingestion of Tryptophan. R. M. Silver et al.; New Eng J Med (Mar 29 1990; 322(13)). Pp. 874-81.

Tryptophan-Induced Eosinophilia-Myalgia Syndrome. T. A. Medsger Jr.; New Eng J Med (Mar 29 1990; 322(13)). Pp. 926-28.


Centers for Disease Control and Prevention

1600 Clifton Road NE

Atlanta, GA 30333

Tel: (404)639-3534

Tel: (800)232-4636

TDD: (888)232-6348

Email: cdcinfo@cdc.gov

Internet: http://www.cdc.gov/

NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases

Information Clearinghouse

One AMS Circle

Bethesda, MD 20892-3675


Tel: (301)495-4484

Fax: (301)718-6366

Tel: (877)226-4267

TDD: (301)565-2966

Email: NIAMSinfo@mail.nih.gov

Internet: http://www.niams.nih.gov/

National Eosinophilia Myalgia Syndrome Network, Inc.

767 Tower Boulevard

Lorain, OH 44052-5213


Tel: (201)868-9572

Email: nemsnnewseditor@gmail.com; elveevee@aol.com

Internet: http://www.NEMSN.org

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/

Madisons Foundation

PO Box 241956

Los Angeles, CA 90024

Tel: (310)264-0826

Fax: (310)264-4766

Email: getinfo@madisonsfoundation.org

Internet: http://www.madisonsfoundation.org

Campaign Urging Research for Eosinophilic Disease (CURED)

PO Box 32

Lincolnshire, IL 60069

Tel: (847)361-3292

Email: ellyn@curedfoundation.org

Internet: http://www.curedfoundation.org

American Partnership for Eosinophilic Disorders

PO Box 29545

Atlanta, GA 30359

Tel: (713)493-7749

Fax: (713)493-7749

Internet: http://www.apfed.org

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.

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