If your child frequently wakes up scratching around the bottom, especially at night, pinworms may be the cause. Pinworm infections are one of the most common intestinal parasite infections in children. Although they can be uncomfortable, they are usually easy to treat and rarely cause serious health problems.
This guide explains what pinworms are, how they spread, the symptoms to watch for, treatment options, and how to prevent reinfection.
Important: The image claims pinworms “bite” children. This is not accurate. Pinworms do not bite. The itching occurs because female worms lay their eggs on the skin around the anus, causing irritation.
What Are Pinworms?
Pinworms (Enterobius vermicularis) are tiny, thin, white worms that live in the large intestine. Adult worms are about the length of a staple (8–13 mm), making them visible to the naked eye in some cases.
They are especially common among:
- Preschool children
- School-age children
- Families with young children
- Childcare centers and schools
How Do Children Get Pinworms?
Pinworms spread easily from person to person.
The cycle usually works like this:
- A child touches a surface contaminated with pinworm eggs.
- The eggs get onto the child’s hands.
- The child puts their fingers in their mouth.
- The eggs hatch in the intestines.
- Female worms travel to the skin around the anus at night to lay thousands of eggs.
- The itching causes scratching, allowing eggs to collect under fingernails and spread to bedding, clothing, toys, and other surfaces.
