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For further information, see CMDT Part 35-22: Hookworm Disease

Key Features

Essentials of Diagnosis

  • Transient pruritic skin rash and lung symptoms

  • Anorexia, diarrhea, abdominal discomfort

  • Iron deficiency anemia

  • Characteristic eggs and occult blood in the stool

General Considerations

  • Infection with Ancylostoma duodenale and Necator americanus is very common, especially in most tropical and subtropical regions

  • When eggs are deposited on warm moist soil they hatch, releasing larvae that remain infective for up to a week

  • With contact, the larvae penetrate skin and migrate in the bloodstream to the pulmonary capillaries

  • In the lungs, larvae penetrate into alveoli and then are carried by ciliary action upward to the bronchi, trachea, and mouth

  • After being swallowed, they reach and attach to the mucosa of the upper small bowel, where they mature to adult worms

    • Worms suck blood at attachment site

    • Blood loss is proportionate to worm burden


  • Prevalence is estimated at about 500 million, causing approximately 65,000 deaths each year

Clinical Findings

Symptoms and Signs

  • Most infected persons are asymptomatic

  • A pruritic maculopapular rash (ground itch) may occur at the site of larval penetration

  • Pulmonary symptoms may be seen during larval migration through the lungs

    • Dry cough

    • Wheezing

    • Low-grade fever

  • Eosinophilia is common, especially during the phase of worm migration

  • About 1 month after infection, gastrointestinal symptoms may develop

    • Epigastric pain

    • Anorexia

    • Diarrhea

  • Persons chronically infected with large worm burdens may have

    • Abdominal pain

    • Anorexia

    • Diarrhea

    • Pallor, weakness, dyspnea, heart failure due to marked iron deficiency anemia

    • Hypoalbuminemia, edema, and ascites due to protein malnutrition

    • May have impairment in growth and cognitive development in children

  • Infection with the dog hookworm Ancylostoma caninum can uncommonly lead to

    • Abdominal pain

    • Diarrhea

    • Eosinophilia

    • Intestinal ulcerations and regional lymphadenitis

Differential Diagnosis

  • Ascariasis

  • Strongyloidiasis

  • Paragonimiasis

  • Tapeworm (especially Diphylobothrium latum with associated anemia)

  • Tuberculosis

  • Allergic bronchopulmonary aspergillosis (ABPA)

  • Mycoplasma pneumoniae infection

  • Iron deficiency anemia due to other causes, eg, gastrointestinal malignancy


  • Diagnosis is based on the demonstration of characteristic eggs in feces

  • Concentration techniques are usually not needed

  • Microcytic anemia, occult blood in the stool, and hypoalbuminemia are common

  • Eosinophilia is common, especially during worm migration



  • Albendazole (single 400 mg orally dose) or mebendazole (100 mg orally twice daily for 3 days)

    • These drugs are teratogenic

    • Occasional adverse effects are diarrhea and abdominal pain

  • Pyrantel pamoate and levamisole are also effective

  • Anemia should be managed with iron replacement and, for severe symptomatic anemia, blood transfusion

  • Mass treatment of children with single doses of albendazole or mebendazole at regular intervals limits worm burdens and the extent of disease and is advocated ...

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