Last reviewed: 23 Aug 2023
Last updated: 04 Jul 2023



History and exam

Key diagnostic factors

  • travel to, or immigration from, endemic areas with poor sanitation, hygiene, and agricultural practices
More key diagnostic factors

Other diagnostic factors

  • asymptomatic
  • co-infection with other parasites
  • developmental delay
  • malnutrition
  • fever
  • cough
  • wheezing
  • dyspnea
  • hemoptysis
  • hypoxia
  • tachypnea
  • rhonchi, rales
  • retractions
  • urticarial skin lesions
  • abdominal pain
  • anorexia
  • dyspepsia
  • nausea
  • vomiting
  • diarrhea
  • constipation
  • abdominal distension
  • reduced or absent bowel sounds
  • hypotension
  • RUQ tenderness
  • hepatomegaly
  • jaundice
  • signs/symptoms of iron deficiency anemia or kwashiorkor
Other diagnostic factors

Risk factors

  • history of travel to or residence in endemic areas
  • children <14 years
  • poverty
  • poor sanitation
  • poor hygiene
  • warm climate
  • contact with pigs
More risk factors

Diagnostic investigations

1st investigations to order

  • stool microscopy
  • chest x-ray
  • abdominal x-ray
More 1st investigations to order

Investigations to consider

  • sputum/gastric aspirate microscopy
  • CBC
  • contrast study
  • barium follow-through
  • abdominal ultrasound
  • abdominal CT
  • ERCP
More investigations to consider

Emerging tests

  • antibodies to Ascaris lumbricoides
  • serum IgE
  • interleukin (IL)-4, IL-5, and IL-13
  • urine-based gas liquid chromatography

Treatment algorithm




gastrointestinal symptoms



Michael Cappello, MD

Professor of Pediatrics, Microbial Pathogenesis, and Public Health

Yale School of Medicine

New Haven



MC declares that he has no competing interests.


Dr Michael Cappello would like to gratefully acknowledge Dr Samantha H. Johnston and Dr Claire Panosian, previous contributors to this topic.


SHJ owns a share in a company (Merck & Co., Inc.) that produces ivermectin, an alternative therapy for ascariasis. CP declares that she has no competing interests.

Peer reviewers

Yann Meunier, MD


Stanford Health Promotion Network

Stanford School of Medicine

Palo Alto



YM declares that he has no competing interests.

Mohammad Bagher Rokni, PhD

Associate Professor

Department of Medical Parasitology and Mycology

School of Public Health

Tehran University of Medical Sciences



MBR declares that he has no competing interests.

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