Rare Diseases 2022

Why urine can smell like fish (and how to treat it)

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Why urine can smell like fish (and how to treat it)
Why urine can smell like fish (and how to treat it)

Urine with a strong fishy smell is usually a sign of fish odor syndrome, also known as trimethylaminuria. This is a rare syndrome that is characterized by a strong, fish-like smell in bodily secretions such as sweat, saliva, urine and vaginal secretions, for example, which can cause a lot of discomfort and embarrassment.

Due to the strong smell, people who have the syndrome tend to take frequent showers, change their underwear several times a day and use very strong perfumes, which do not always help to improve the odor. In these cases, it is recommended to control the syndrome through diet, in which foods that originate the substance trimethylamine, such as fish and egg yolk, for example, should be avoided.

Why does this syndrome happen?

This syndrome is caused by a genetic alteration that causes a deficiency in a compound in the body responsible for degrading trimethylamine, which is a nutrient found mainly in fish, shellfish, liver, peas and egg yolks, for example. This causes this substance to accumulate in the body and be exhaled from the body, as it is a substance that evaporates.

However, despite being caused primarily through genetic alterations, some people who do not have this alteration may also experience similar symptoms when taking medications that cause trimethylamine to accumulate, such as Tamoxifen, Ketoconazole, Sulindac, Benzidamine and Rosuvastatin, for example.

Main symptoms of the syndrome

The only symptom related to this syndrome is the smell of rotten fish that is exhaled from the body, mainly through bodily secretions such as sweat, breath, urine, expired air and vaginal secretions, for example.Symptoms can appear in childhood, when the child stops being breastfed and starts to eat a normal diet, and can worsen during adolescence, especially during menstruation, and can also worsen with the use of contraceptives.

Normally, those who have this syndrome tend to take several showers throughout the day, constantly change their clothes and even avoid socializing with other people. This happens due to the embarrassment that occurs when the smell is perceived and commented on, for example, which can also favor the development of psychological problems, such as anxiety or depression.

How to confirm the diagnosis

The diagnosis of fish odor syndrome is made by means of a blood test, scraping of the mucous membrane of the mouth or a urinalysis in order to verify the concentration of the substance responsible for the unpleasant odor, trimethylamine.

How the treatment is done

This syndrome has no cure and its treatment is done to control and reduce the bad smell, by reducing the consumption of foods that increase this symptom, such as those rich in the nutrient choline, which are fish, shellfish, meat, liver, peas, beans, soybeans, nuts, egg yolks, cabbage, cauliflower, brussels sprouts and broccoli. See the amount of choline in foods.

However, it is important to remember that pregnant women should not restrict these foods in their diet, as some fish, for example, are important for the development of the baby's nervous system, and it is important to consume them during pregnancy even if there is increased smell.

In addition, antibiotics can also be used to control the intestinal flora, one of those responsible for the fishy odor. Other tips to neutralize the smell are using soaps with a pH between 5.5 and 6.5, goat's milk soap, skin creams with a pH around 5.0, washing clothes frequently and taking activated charcoal tablets., according to medical recommendation.To alleviate the smell, also see how to treat the smell of sweat.

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