Pinworm infection

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Pinworm infection is caused by the intestinal roundworm Enterobius vermicularis. This infection typically affects children. This is the most prevalent form of roundworm infection among children in various places all over the globe.

How it spreads

The infection occurs after the pinworm eggs are ingested. The larvae hatch in the small intestine and then move to the large intestine. Once there, the larvae mature within 2-6 weeks and the adult worms mate.

As the eggs develop, the adult female worm travels to the rectum and departs via the anus to lay eggs. These eggs are deposited into an adhesive, gel-like substance that sticks to the skin around the anus. From there, the eggs can transfer to fingernails, toys, clothing, bedding or food. These eggs can survive outside the body for up to 3 weeks at normal room temperature.

Pinworm infection
Many children who are carriers of pinworms do not have any symptoms.

What are the indications of pinworm infection?

Many children who are carriers of pinworms do not have any symptoms. Nevertheless, in some cases, the area surrounding the anus becomes itchy since the eggs and the sticky substance around them irritates the skin.

If scratched, the skin turns raw and infected with bacteria. Among girls, the pinworms might cause vaginal itchiness and irritation.

How is it diagnosed

A diagnosis of pinworm infection is done by finding eggs or even adult pinworms around the anus. The eggs can be obtained by patting the skinfolds around the anus with the adhesive side of a transparent tape. The eggs must be obtained early in the morning before the child defecates or wipes the area. This tape is taken to the doctor for microscopic analysis.

The ideal way to search for adult pinworms is to check the anus of the child for about 1-2 hours after been put to bed for the night. The worms are white and hair-thin but can wiggle and visible to the naked eye.


One dose of mebendazole or albendazole that is repeated 2 weeks usually cures the pinworm infection.

Despite successful treatment of the pinworm infection with drugs, reintroduction of the infection is common, partly because the eggs are capable of surviving outside the body for up to 3 weeks. It is even recommended that the entire family is treated. Bedding, clothing and toys must be washed regularly and the environment is vacuumed to eliminate the eggs.

Anti-itch ointments or creams such as carbolated petrolatum should be applied directly to the area around the anus to alleviate the symptoms.

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