Enterobius vermicularis

Topic Completed: 1 August 2012

Minor changes: 24 October 2019

Copyright: (c) 2003-2019,, Inc.

PubMed Search: Enterobius vermicularis appendix

See Also: Parasitology chapter

Page views in 2019: 7,110
Page views in 2020 to date: 3,686
Cite this page: Mansouri J. Enterobius vermicularis. website. Accessed August 6th, 2020.
Definition / general
  • Also known as pinworm
  • Formerly known as oxyuris vermicularis, oxyuriasis
  • Most common helminthic infection in children, affects all social strata in the U.S.

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Life cycle

Clinical features
  • Usually more common in temperate climates
  • Usually found in appendix of children ages 7 - 11 years as incidental finding
  • Mass of worms may cause obstruction
  • May occasionally be associated with appendicitis (Pediatr Surg Int 2004;20:372, Southeast Asian J Trop Med Public Health 2007;38:20)
  • Eggs often deposited at night on perianal skin, causing pruritis ani, irritability, loss of sleep (DPDx - Enterobiasis)
  • Eggs can be diagnosed with the cellulose tape technique on perianal skin when child wakes up
  • Adult worms may migrate to the lower genital tract and cause a granulomatous reaction
Case reports
Gross description
  • Worms reside in cecum, 1.3 cm long
Microscopic (histologic) description
  • Cross section has narrow lateral cuticular alae
Microscopic (histologic) images

Case of the Week #90


Contributed by Dr. Wafaey Fahmy Badawy Mohamed, Armed Forces Hospital, Hafr Albatin, Saudi Arabia

8 year old child, presenting with acute appendicitis

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Enterobius in appendix

Cytology images

Contributed by Dr. Guido Nicolò (Italy)

Enterobius vermicularis

Contributed by Dr. C. Shrinivasan, Sterling Hospital, Vadodara, Gujarat (India)

Ova and larva of Enterobius vermicularis

Contributed by Centers for Disease Control and Prevention


Differential diagnosis
  • Vegetable matter, whipworm
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