Description

• Intestinal infection with Enterobius vermicularis
  • Characterized by perineal and perianal itching
  • Usually worse at night
• System(s) affected: gastrointestinal; skin/exocrine
• Synonym(s): enterobiasis

Epidemiology

Predominant age: 5 to 14 years

Prevalence

• Most common helminthic infection in the United States
  • 20 to 42 million people harbor the parasite.
• ~30% of children are infected worldwide.

Pediatric Considerations
More common in children, who are more likely to become reinfected

Etiology and Pathophysiology

• Small white worms (2 to 13 mm) inhabit the cecum, appendix, and adjacent portions of the ascending colon following ingestion; associated with multiple case reports of appendicitis
• Female worms migrate to the perineal areas at night to deposit eggs; this causes local irritation and itching.
• Scratching leads to autoingestion of the eggs and continuation of pinworm’s life cycle within the host. Eggs incubate 1 to 2 months in the host small intestine. When mature, female pinworms migrate to the colon where they lay eggs around the anus at night, and the lifecycle continues.
• Infestation by the intestinal nematode E. vermicularis (1)

Risk Factors

• Institutionalization (prevalence >50%)
• Crowded living conditions
• Poor hygiene
• Warm climate
• Handling of infected children’s clothing or bedding

General Prevention

• Hand hygiene, especially after bowel movements
• Clip and maintain short fingernails.
• Wash anus and genitals at least once a day, preferably during shower.
• Avoid scratching anus and putting fingers near nose (pinworm eggs can also be inhaled) or mouth.

Commonly Associated Conditions

• Pruritus ani
• Appendicitis