I have an adult patient who says that whenever he eats crustaceans or mollusks he, within hours begins to give off a body odor which smells like fish. This odor will last for several hours and is very noticeable to others around him. It is very embarrassing to him and wonders what causes it and if there is anything he can do about it. He loves seafood and does not want to give up eating it. Any thoughts?


Thank you for your inquiry.

I am afraid I do not have a definitive answer to this problem. The only documented disorder of which I am aware that could possibly account for your patient’s symptoms is trimethylaminuria. In some individuals, there is defective catabolism of trimethylamine which is due to trimethylamine oxidase deficiency. Thus trimethylamine accumulates in the blood and appears in the uine and and sweat. Patients with this disorder have a problem with body odor which can be increased with the ingestion of certain foods.

Of course I am not sure that your patient has this condition, but I could think of no other medical problem that might account for this symptom complex. Copied below you will see abstracts of articles that will give you more information and delineate how to test for this disorder.

Thank you again for your inquiry and we hope this response is helpful to you.

Drug Metab Dispos. 2001 Apr;29(4 Pt 2):517-21.
Trimethylaminuria: the fish malodor syndrome.
Mitchell SC, Smith RL.
Section of Molecular Toxicology, Division of Biomedical Sciences, Imperial College School of Medicine, Sir Alexander Fleming Building, South Kensington, London, England.
The fish malodor syndrome (also known as the fish odor syndrome and trimethylaminuria) is a metabolic disorder characterized by the presence of abnormal amounts of the dietary-derived tertiary amine, trimethylamine, in the urine, sweat, expired air, and other bodily secretions. Trimethylamine itself has the powerful aroma of rotting fish, and this confers upon the sufferer a highly objectionable body odor, which can be destructive to the personal, social, and work life of the affected individual. In recent years, much progress has been made at all levels-clinical, epidemiological, biochemical, and genetic-in our understanding of this unfortunate condition. The present article summarizes this progress, draws attention to the different types of fish malodor syndrome, and highlights the current needs in the treatment of such patients.

Endocrinol Nutr. 2009 Jun-Jul;56(6):337-40. doi: 10.1016/S1575-0922(09)71948-5.
[Primary trimethylaminuria: the fish odor syndrome].
[Article in Spanish]
Montoya Alvarez T, Guardiola PD, Roldán JO, Elviro R, Wevers R, Guijarro G.
Servicio de Endocrinología y Nutrición, Hospital Infanta Elena, Madrid, España.
Primary trimethylaminuria, or fish odor syndrome, is a congenital metabolic disorder characterized by a failure in the hepatic trimethylamine (TMA) oxidation route to trimethylamine N-oxide (TMANO). TMA is mostly derived from dietary precursors such as choline, carnitine and TMANO. The presence of abnormal amounts of TMA in the urine, sweat, exhaled air and other body secretions confers a very unpleasant body odor resembling that of decaying fish. As a consequence, patients can suffer from serious psychosocial sequelae. We present a case of primary trimethylaminuria with the aim of raising awareness about this condition.

Phil Lieberman, M.D.

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