Pinworms common in kids under age 10


Dear Doctors: How on Earth did my son get pinworms? I didn’t even realize something was wrong until he started scratching his butt in his sleep. The minute we told his pediatrician about the scratching, she suspected pinworms. Does this mean the rest of the family has been exposed?

Dear Reader: Pinworm is the common name for a small, pale roundworm known as Enterobius vermicularis. They are also sometimes called threadworms due to their slender, threadlike appearance. These tiny parasites, which are about the length of a staple, are the most common cause of worm infections in the United States.

Pinworms live in the colon and the rectum of humans, who are their sole hosts. Pinworms do not live in animals. In order to lay eggs, a female pinworm travels from the colon to the tissues of the anus. This typically happens at night. It often results in intense itching that can wake someone from sleep. That’s the symptom that led your son’s pediatrician to suspect a pinworm infection. The reassuring news is that while pinworms are a little gross, certainly annoying and perhaps embarrassing, they are easily treated and seldom cause serious health problems.

It’s possible but rare for pinworms to travel from the anus to the vagina. This is typically associated with heavy infestations that go untreated and can lead to a urinary tract infection, and also possibly affect the pelvic organs.

A pinworm carrier can easily spread the infection. Whenever an infected person fails to thoroughly wash their hands after using the bathroom or scratching their anus, they can transfer microscopic eggs to any surfaces that they touch. When someone touches that surface, and then later touches their mouth, they can become infected. The eggs travel through the digestive tract to the colon. Once there, they hatch and, within a few weeks, grow into mature worms.

Diagnosis is made by identifying the worm or its eggs. Worms may be visible on the skin near the anus a few hours after falling asleep. Sticky tape can be used to collect eggs from the anus in the morning, and then given to your doctor to be examined.

Elizabeth Ko, MD and Eve Glazier, MD

Although anyone can become infected with pinworms, it’s most common in children younger than 10 years old. Kids that age often have their fingers in their mouths, and they aren’t always great about washing their hands. Schools, preschools and day care centers are common sources of pinworm infection. You asked if your son’s infection means your family has been exposed, and the answer is that it’s quite likely. Anyone living with or caring for an individual with pinworms is at risk of infection.

To stop the cycle of infection, it is recommended to treat everyone who may have been exposed. This may consist of a single dose of an over-the-counter medication known as pyrantel pamoate, which paralyzes the worms and allows the body to safely remove them via the stool. Although available without a prescription, we strongly recommend that this medication be used under medical supervision. Several prescription anti-parasite medications are also extremely effective. Anyone who suspects a pinworm infection should see their health care provider for diagnosis and treatment.

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