"Toxic sock" syndrome.

For several months, a 17-year-old male athlete noticed that his feet had an itchy, burning sensation at the heels and toes. His foot odor had become so malodorous (somewhat akin to rotting fish) that he would not remove his shoes except immediately before washing his feet. Washing made the odor somewhat milder, but only for a short time. The patient had tried an over-the-counter "athlete's foot" powder without results. He had no other health problems and was not taking any medication. The accompanying figure shows the toes of his right foot.