eMedicine Specialties > Emergency Medicine > Infectious Diseases

Pinworms

Author: Joseph J Bocka, MD, Director of Shelby Emergency Department, Attending Emergency Physician at Mansfield Hospital, Med Central Health System (Mansfield and Shelby, Ohio); Emergency Medical Service Medical Director for several services
Contributor Information and Disclosures

Updated: Aug 12, 2009

Introduction

Background

Enterobius vermicularis (pinworm) is the most common intestinal parasite in the United States. Despite primarily living in the gut, the most common chief complaint is anal itching (pruritus). Most patients with pinworm infestation, however, are asymptomatic.

Pinworms in a young patient.

Pinworms in a young patient.

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Pinworms in a young patient.

Pinworms in a young patient.

Pathophysiology

E vermicularis lives in the small intestines, primarily the ileocecal region. The gravid female migrates to the anus and deposits eggs in the perianal skin folds, usually at nighttime. The movement of the female and the ova cause intense local itching. Ova may survive for up to 3 weeks before hatching. The hatched larvae can then migrate back into the anus and lower intestine, causing retroinfection. Embryonated eggs may be released into the air or onto fomites (eg, bedding, clothing, toys, paper money) or onto hands and then placed directly into the mouth and swallowed (autoinfection), after which they settle in the small intestines.

Frequency

United States

E vermicularis is the most common helminth in the United States. General prevalence in children is reported to be 0.2-20%. Prevalence in institutionalized persons is reported to be 50-100%.

International

A similar prevalence of pinworm infestation has been reported in European countries.

Mortality/Morbidity

Pinworm infestation is very rarely fatal; death and morbidity are from secondary infection. A 28-68% increased risk for appendicitis is associated with pinworm infestation.1

Sex

Overall, males are affected twice as often as females are except in people aged 5-14 years, when females predominate.

Age

School-aged children have the highest prevalence of pinworm infestation.

Clinical

History

  • Most patients with pinworm infestation are asymptomatic.
  • The most common complaint is anal itching (pruritus), usually nocturnal or in the early morning.
  • Other possible complaints include the following:
    • Abdominal pain (even mimicking an acute surgical process)
    • Irritability
    • Restlessness
    • Vaginal itching
    • Pelvic pain2

Physical

  • Perianal excoriations secondary to scratching may be found.
  • The pale-colored female pinworm (10 mm; male 3 mm) may be visibly seen in the perianal region.
  • Eggs (30 μ m X 50-60 μ m) are usually not seen without a microscope.

More on Pinworms

Overview: Pinworms
Differential Diagnoses & Workup: Pinworms
Treatment & Medication: Pinworms
Follow-up: Pinworms
Multimedia: Pinworms
References
Further Reading
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References

  1. Ramezani MA, Dehghani MR. Relationship between Enterobius vermicularis and the incidence of acute appendicitis. Southeast Asian J Trop Med Public Health. Jan 2007;38(1):20-3. [Medline].

  2. Erian M, McLaren G. Unexpected causes of gynecological pelvic pain. JSLS. Oct-Dec 2004;8(4):380-3. [Medline].

  3. Aydin O. Incidental parasitic infestations in surgically removed appendices: a retrospective analysis. Diagn Pathol. 2007;2:16. [Medline].

  4. Ajao OG, Jastaniah S, Malatani TS, et al. Enterobius vermicularis (pin worm) causing symptoms of appendicitis. Trop Doct. Jul 1997;27(3):182-3. [Medline].

  5. Arca MJ, Gates RL, Groner JI, et al. Clinical manifestations of appendiceal pinworms in children: an institutional experience and a review of the literature. Pediatr Surg Int. May 2004;20(5):372-5. [Medline].

  6. Hong ST, Choi MH, Chai JY, Kim YT, Kim MK, Kim KR. A case of ovarian enterobiasis. Korean J Parasitol. Sep 2002;40(3):149-51. [Medline].

  7. Hugot JP, Reinhard KJ, Gardner SL, Morand S. Human enterobiasis in evolution: origin, specificity and transmission. Parasite. Sep 1999;6(3):201-8. [Medline].

  8. Jardine M, Kokai GK, Dalzell AM. Enterobius vermicularis and colitis in Children. J Pediatr Gastroenterol Nutr. Nov 2006;43(5):610-2. [Medline].

  9. Jeske J, Kamerys J, Ochecka-Szymanska A. Efficacy of mebendazole in treatment of selected parasitoses--a retrospective study. Wiad Parazytol. 2000;46(1):127-39. [Medline].

  10. Gilbert DN, Moellering RC, Eliopoulos GM, et al. The Sanford Guide to Antimicrobial Therapy 2007. Sperryville, Va: Antimicrobial Therapy Inc; 2007:127,133.

  11. Wang LC, Hwang KP, Chen ER. Enterobius vermicularis infection in schoolchildren: a large-scale survey 6 years after a population-based control. Epidemiol Infect. May 19 2009;1-9. [Medline].

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Keywords

pinworm, pin worm, Enterobius vermicularis, E vermicularis, enterobiasis, intestinal parasite, anal itching, pinworm infestation

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Contributor Information and Disclosures

Author

Joseph J Bocka, MD, Director of Shelby Emergency Department, Attending Emergency Physician at Mansfield Hospital, Med Central Health System (Mansfield and Shelby, Ohio); Emergency Medical Service Medical Director for several services
Joseph J Bocka, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, National Association of EMS Physicians, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

David A Peak, MD, Assistant Residency Director of Harvard Affiliated Emergency Medicine Residency, Attending Physician, Massachusetts General Hospital; Consulting Staff, Department of Hyperbaric Medicine, Massachusetts Eye and Ear Infirmary
David A Peak, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, Society for Academic Emergency Medicine, and Undersea and Hyperbaric Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Jeter (Jay) Pritchard Taylor III, MD, Compliance Officer, Attending Physician, Emergency Medicine Residency, Department of Emergency Medicine, Palmetto Health Richland, University of South Carolina; Medical Director, Department of Emergency Medicine, Palmetto Health Baptist
Jeter (Jay) Pritchard Taylor III, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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