'Fish odor syndrome': A rare metabolic condition that makes sweat smell like rotten fish

A close-up image of a man in a blue shirt touching a sweat patch under his armpit.

Disease name: Trimethylaminuria (TMAU), also known as "fish odor syndrome"

Affected populations: TMAU is a rare metabolic condition that causes a person to smell like rotten fish. The condition is more common in women than in men, and there's evidence that female sex hormones, such as progesterone, can exacerbate patients' symptoms.