What kind of worms is that

Pinworm infestation (Enterobiasis, Worms in the stool, worms)

Pinworms are a special type of parasite, i.e. living beings that live in another organism and feed at its expense. An infection with pinworms is known as enterobiasis.

Short version:

  • It is estimated that more than a billion people worldwide are affected by pinworms.
  • The worms are very robust and can survive for a long time on clothes, bed linen or toys.
  • Pinworms in stool can sometimes be seen with the naked eye.
  • Pinworms are treated with a drug that kills parasites.
  • You can prevent pinworm infection by washing your hands regularly.

What are pinworms?

Pinworms (Enterobius vermicularis) live in the large intestine of humans. In many countries the pinworm is the most common parasite. Mainly children become infected between 4 and 11 years, but occasionally also adults. It is estimated that more than a billion people are infected worldwide. Optically, pinworms have a "maggot-like" appearance, which is reflected in the German naming.

Pinworms and their eggs are extremely resistant and can survive for a long time on furniture, bed linen, clothes or toys. With a length of 9–12 mm and a diameter of 0.5 mm, the female worms are larger than the males, which reach a size of approx. 3–5 mm. Both can be seen with the naked eye. They have a round body, a white-beige color and move crawling.

Female worms can carry over 10,000 eggs. These eggs can survive for several days on inanimate surfaces. It is important to know that pinworms specialize in humans as hosts. In contrast to other worm diseases, pets therefore do not play a special role.

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How does the infection with pinworms occur?

The pinworm spreads mainly through poor hygiene and insufficient hand washing. If, for example, sand comes from the sandpit, from contaminated objects or from unwashed food into the mouth, the eggs of the pinworm get into the child's body. There the larvae develop within 4–8 hours and hatch in the small intestine. After shedding their skin twice, the motile worms migrate towards the large intestine. The male worms die very quickly compared to the female ones, while the latter can live up to 100 days.

Eggs are laid mainly at rest, i.e. at night when the child is asleep. Then the female pinworms crawl out of the anus and lay their eggs in the area of ​​the anal folds, in the immediate vicinity of the intestinal anus. You fix them with a sticky secretion. Due to the secretion, egg-laying is often associated with itching and severe scratching, which promotes additional distribution of the eggs.

In addition, when the children scratch their anus, the eggs get stuck under their fingernails. If the child touches objects or then puts their fingers in their mouth, they will be infected again and again. Infected children easily transmit the pinworms to other children or family members, for example through close physical contact, food or sharing towels.

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What are the symptoms of pinworms?

There are no typical signs of illness. In up to 40% of the cases, there are no symptoms at all. However, the following symptoms may indicate an infection with pinworms:

  • frequent itching in the anus area
  • chronic abdominal pain
  • chronic constipation
  • repeated vaginal infections
  • Bed-wetting after the child was already "clean"
  • Female worms that may have died overnight are visible in pajamas, bed linen or stools
  • general malaise

How are pinworms diagnosed?

The doctor examines the abdomen and the area of ​​the anus. An anal swab may have been done in the past. Most of the time, however, the typical symptoms are sufficient for a suspected diagnosis. A single living / dead worm or the detection of eggs on the smear under the microscope is sufficient for a reliable diagnosis. Pinworms can sometimes also be detected in a stool sample or during a colonoscopy.

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How is pinworm treated?

To avoid further transmission, pinworms are definitely treated if symptoms are severe. Family members should look out for similar symptoms, be examined if necessary and, under certain circumstances, treated as well.

Medicines such as:

  • Pyrantel embonate
  • Mebendazole
  • Pyrvinium embonate
  • Albendazole

After 7 (and possibly 14) days, the therapy is repeated to kill any surviving worms or eggs. In addition, hygienic care is particularly important and those affected are informed about the clinical picture and the possible transmission routes. Other recommended actions are:

  • after a wormer treatment: whites for pajamas, underwear and all bed linen
  • Cut nails short
  • Wash your hands thoroughly before eating and after using the toilet
  • Avoid scratching as much as possible
  • Avoiding anus-finger-mouth contact as much as possible
  • Regular washing of underwear and pajamas
  • no sharing of towels or washcloths

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Complications from pinworm infestation

Girls and women who spread the worm eggs by scratching frequently can develop vaginal infections (vulvovaginitis). Rarely, pinworm infection can lead to weight loss. Pinworms have adapted perfectly to their habitat in the large intestine, but in exceptional cases other organ systems can be infested.

How can you prevent pinworm infection?

  • Wash your hands regularly and do not put any objects in your mouth
  • Cut fingernails as short as possible
  • changing clothes regularly
  • thorough and regular cleaning of the anal region

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Dr. Edgar Tichatschek (2015), Christopher Waxenegger (2020)
Medical review:
Priv.-Doz. GDR. Tamás Fazekas
Editorial editing:
Astrid Leitner

Status of medical information:

Wendt S, Trawinski H, Schubert S, Rodloff AC, Mössner J, Lübbert C. The diagnosis and treatment of pinworm infection. Dtsch Arztebl Int 2019; 116: 213-19

Lennecke K, Hagel K: Self-medication - guidelines for pharmaceutical advice. Deutscher Apotheker Verlag, Stuttgart, 6th edition, 2016

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