Army of worm larvae hatch from man’s bum, visibly slither under his skin

A man in Spain was diagnosed with an unusual roundworm after doctors saw an army of worms under his skin.

Doctors reported the man's rare hyperinfection this week in the New England Journal of Medicine, showing the unusual sight of a wriggling, sliding skin rash that tracked the movements of individual parasites. The official diagnosis was a larva from Strongyloides.

The unfortunate patient appeared to have a perfect storm of risk factors that led to the unpleasant and uncommon infection. The man who worked in sewage management was previously diagnosed with lung cancer. Doctors had noted bouts where he had high levels of disease-fighting white blood cells, which can be an indicator of a parasites.

The man was in the hospital because of a growth on his spine. Doctors had treated him with a high dose of glucocorticoid, which suppresses some immune responses and creates prime conditions for parasites to flourish.

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Vermin invasion

The worm in this case is Strongyloides stercoralis, a nematode or roundworm known to infect people. Infections begin when a person is exposed to contaminated soil or sewage. The worms can mature and breed there, and legions of little larvae—about 600 micrometers in length—can emerge, burrow directly into a person's skin unnoticed, and make their way into the intestines by various routes. In some instances, the larvae make their way to the lungs, get coughed up, and then swallowed to reach their final destination. Once in the intestines, the worms embed themselves in the mucosa of the small intestines and reproduce. Larvae that hatch there are then shed in feces to start the process again—or penetrate the skin in the perianal area, resulting in an "auto-infection."

What appears to have happened in the cancer patient is the most disturbing cycle. The problems began with a raised, itchy rash. The red, wavy skin on his body began in his perianal region and spread all over his body. The doctors noted that the red squiggles had moved after they wrote them on his skin with a pen.

The diagnosis was made by the shifting rash and the identification of Strongyloides stercoralis in a stool exam. Doctors prescribed the man an anti-parasitic drug.