Something’s fishy, but it’s just genetic
Americans are obsessed with smelling good, spending billions each year on perfumes, colognes and deodorant. But for some rare individuals, no amount of sprayed, lathered, splashed or rolled-on fragrance can do the trick; their body odor is in their genes.
Fish malodor syndrome -- trimethylaminuria, or TMAU -- is caused by the malfunction of an enzyme that breaks down the amino acid trimethylamine, or TMA, the same compound that makes decomposing fish smell fishy. When TMA builds up in the body, it gets excreted in urine, sweat and breath, resulting in a fishy miasma.
Doctors believe fish malodor syndrome is age-old. In an ancient Hindu epic poem, a woman is outcast for her fishy smell. In a centuries-old Thai folk tale, characters commit suicide because of their fishy body odor. And in Shakespeare’s “The Tempest,” Caliban is banished to an island for his offensively fish-like smell.
But fish malodor syndrome came under modern medical scrutiny only in 1970, when a Colorado woman brought her 6-year-old daughter into the local university medical center because she smelled like fish.
On examination, the doctors found high levels of TMA in the girl’s urine. Her odor increased when they gave her high doses of TMA -- this didn’t happen when they gave similar doses to controls.
Scientists now know the disorder is hereditary; they found the gene responsible for it in 1997. They also know it’s more common in adults than children, in women than men. It affects some breeds of chicken, which lay fishy-smelling eggs.
Because the condition is so rare, few doctors have encountered it -- and most sufferers spend five to 10 years getting diagnosed. Treatment often involves going on a special diet, in which eggs, peas, beans, fish and soy are avoided for the TMA precursors they contain.
Prospects are brighter for people with more common sources of odor, such as hard workouts on hot days and gorging on garlic -- even growth of certain bacteria and fungi, which can be treated .
In people with bromhidrosis, bacteria on skin decompose sweat secretions, yielding a putrid smell. In those with erythroderma, proliferation of bacteria on scaly skin causes a musty stench. In erythrasma, unpleasant-smelling bacteria grow in skin folds. And in some forms of athlete’s foot, the stench comes from the Trichophyton fungus growing on feet.
One of the rarest conditions sending people to the doctor out of concern for their bodily odor is caused by neither odor-causing genes nor microbes. In cacosmia, from Greek for “bad” (kakos) and “sense of smell” (osme), the problem lies with neurons that process odors.
Fortunately for those around them, people with cacosmia don’t actually smell bad. But unfortunately -- and frustratingly -- for themselves, they are resolutely convinced that they do.
