Ascaris Lumbricoides Clinical Presentation

Updated: Jan 15, 2019
  • Author: Aaron Dora-Laskey, MD, MS; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
  • Print


Most patients are asymptomatic. When symptoms occur, they are divided into 2 categories: early (larval migration) and late (mechanical effects).

In the early phase (4-16 d after egg ingestion), respiratory symptoms result from the migration of larvae through the lungs. Classically, these symptoms occur in the setting of eosinophilic pneumonia (Löffler syndrome).

  • Fever

  • Nonproductive cough

  • Dyspnea

  • Wheezing

In the late phase (6-8 wk after egg ingestion), gastrointestinal symptoms may occur and are more typically related to the mechanical effects of high parasite loads.

  • Passage of worms (from mouth, nares, anus)

  • Diffuse or epigastric abdominal pain

  • Nausea, vomiting

  • Pharyngeal globus, "tingling throat"

  • Frequent throat clearing, dry cough

  • Complications - Mechanical small bowel obstruction, volvulus, intussusception, biliary obstruction, appendicitis, pancreatitis



General symptoms include the following:

  • Fever

  • Jaundice (in biliary obstruction)

  • Cachexia (due to malnutrition)

  • Pallor (anemia)

  • Urticaria (early infection)

Pulmonary symptoms include the following:

  • Wheezing

  • Rales

  • Diminished breath sounds

Abdominal symptoms include the following:

  • Abdominal tenderness, which may be diffuse (in obstructive infections), epigastric (pancreatitis), or localized to the right lower (appendicitis) or right upper quadrant (hepatobiliary infections)

  • Peritoneal signs in cases of bowel perforation

  • Obstructive symptoms (nausea/vomiting/constipation/distention)

Migrating larvae may transmit other organisms, causing bacterial pneumonia or cholangitis. Rare cases of airway obstruction and laryngeal spasm [7] have also been reported. Other much less common presentations include lacrimal drainage obstruction, [8] small bowel intussusception, [9] acute interstitial nephritis, [10] urinary tract obstruction, [11] and encephalopathy. [12]



Symptoms are typically associated with early larval migration, heavy intestinal burdens of adult worms, or aberrant worm migration. Worm migration may be stimulated by anesthetic agents, fever, or subtherapeutic anthelmintic treatment, or by use of certain anthelmintics (eg, pyrantel pamoate).



Complications may be attributed to larval migration typically involving the lungs, and intestinal tract producing vague symptoms but may as well involve the kidneys, brain, and heart.

Severe complications later in disease are usually attributable to mechanical obstruction of intestines or biliary tree secondary to high worm burden.

Complications may arise early in disease due to allergic reaction to Ascaris infection (urticaria).

Malnutrition, anemia, growth, and developmental retardation (subject to some debate)