What are Threadworms?

Threadworms are small, parasitic worms that infect the human intestine. Also called pinworms, the worms are white and resemble pieces of thread. They can hatch eggs within the gut and multiply causing infestation. Threadworms are most common among children under 10 years of age but can also be seen in adults.

Many people do not have symptoms of threadworm but symptoms that may present include:

  • Itching around the anus, bottom or vagina
  • The itching is usually worse at night and may interfere with sleep
  • Small, thread-like, white worms may be visible around the anus or in stools
  • Many people do not have symptoms


The worms migrate towards the anus to lay their eggs at night. Along with an average of 11,000 eggs, the worms also secrete a mucus in the area that causes itching. If an infected person scratches the area, the eggs are easily picked up by the fingertips or under the finger nails, from where they be transmitted to the mouth or to surfaces that other uninfected individuals may touch.

The eggs are resilient and can survive for up to three weeks before they hatch. If they hatch around the bottom of the individual, they re-enter the bowels or gut as tiny new born worms. If the eggs have entered via the mouth, they pass through the gut to reach the large intestine. It takes around 2 weeks for the worms to become adults and begin laying eggs.

Diagnosis and treatment

Diagnosis is commonly made based on symptoms. In addition, stool samples may be examined under the microscope for presence of the worms, to confirm the diagnosis.

Treatment should be administered to everyone living in the same household as the infected individual, as the risk that the infection will spread is very high. The usual treatment used is a single dose of albendazole, mebendazole or piperazine.

Mebendazole or piperazine may be repeated after two weeks, if necessary. Mebendazole is preferred for adults and children over two years of age, while piperazine can be given to children aged between three months and two years.

Aside from treating the infection with drugs, it is important to maintain personal hygiene to prevent spread. The hands should be washed after going to the toilet, before meal times and before preparing food. In addition, bathroom surfaces need to be kept clean.

Further Reading

Last Updated: Jan 2, 2023

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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