A woman took a trip to the Caribbean and shortly after she got home, she developed a rash on her knee that just wouldn’t go away. She went to the doctor, who sent her on to the emergency room. She was shocked to find out it wasn’t a rash at all but a parasitic worm. Dr. Chaiya Laoteppitaks of the Albert Einstein Medical Center in Philadelphia said that the woman had a textbook case of cutaneous larva migrans.
Laoteppitaks and his colleagues published a case report in the Journal of Emergency Medicine on April 8, in which they state that cutaneous larva migrans is caused by a hookworm infection.
Typically found in warm, moist regions of the world, hookworms infect people when their larvae tunnel underneath the skin. The larva proceeds to travel through the body until it reaches the small intestine, at which point it matures and lays eggs. The eggs are then excreted from the body in the person’s feces, and the life cycle begins again.
The woman’s case is unusual in that the hookworm species that caused her infection — one of the two worms known scientifically as Ancylostoma braziliense or Ancylostoma caninum — usually infect dogs and cats, not humans, reports Live Science.
Because humans are not a “definitive host” for these hookworms, Laoteppitaks explained they are unable to complete their life cycle in a human’s body. Because of this, they burrow around until they die.
The itchy rash is caused by the body’s attempt to eradicate the worm. The worms can travel an inch a day as the burrow through the body. The hook worms cannot complete their life cycle in a human body, so they keep burrowing until they die.