The fertilized female worm(s) (which measures from 60–100 cm long) migrates under the skin tissues until it reaches the lower limbs, forming a blister or swelling from which it eventually emerges.

Now a new study supports the hygiene hypothesis: infants in Uganda had a lower chance of developing the skin allergy condition eczema if their moms had helminth worm infections while pregnant.

Then the worm makes its way toward the skin surface.