What is the expected visibility of worms after a child defecates in pinworm diagnosis?

• A. Worms will be visible.
• B. Worms will not be visible.
• C. Worms are visible only with a microscope.
• D. Worms will migrate to the stool without leaving the perianal area.

Answer: (B)

Pinworms cause itching around the anus because the female worms migrate to the perianal area at night to lay eggs. They spend most of their life in the large intestine, so they aren’t usually present in stool. Because of this, you wouldn’t expect to see worms in the stool after defecation. That’s why the standard diagnosis isn’t based on finding worms in stool; it relies on catching eggs around the perianal area with a sticky tape test first thing in the morning and examining that specimen under a microscope. In short, worms will not be visible in the stool after defecation.