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For further information, see CMDT Part 16-02: Acute Hepatitis A

Key Features

Essentials of Diagnosis

  • Prodrome of anorexia, nausea, vomiting, malaise, aversion to smoking

  • Fever, enlarged and tender liver, jaundice

  • Normal to low white blood cell count; markedly elevated aminotransferases

General Considerations

  • Transmission of hepatitis A virus (HAV) is by the fecal-oral route by either person-to-person contact or ingestion of contaminated food or water

  • The incubation period averages 30 days

  • HAV is excreted in feces for up to 2 weeks before the clinical illness and rarely persists in feces after the first week of illness

  • There is no chronic carrier state


  • Globally, 15 million people are infected with HAV annually

  • HAV spread is favored by crowding and poor sanitation

  • HAV infection is hyperendemic in developing countries

  • Common source outbreaks result from contaminated water or food

  • In 2017, an outbreak beginning in California and extending to 33 other states affected a large number of homeless persons and resulted in many deaths

  • Outbreaks have been reported among injection drug users

  • Since introduction of HAV vaccine in the United States in 1995, the incidence rate of HAV infection has declined from 14 to 0.4 per 100,000 population

  • Over 80% of persons aged 20–60 years in the United States are still susceptible to HAV, and vulnerable populations are especially at risk

  • The highest incidence rate (2.1 per 100,00) is in adults aged 30–39

Clinical Findings

Symptoms and Signs

  • Onset may be abrupt or insidious

  • Malaise, myalgia, arthralgia, easy fatigability, upper respiratory symptoms, and anorexia

  • A distaste for smoking, paralleling anorexia, may occur early

  • Nausea and vomiting are frequent, and diarrhea or constipation may occur

  • Defervescence and a fall in pulse rate often coincide with the onset of jaundice

  • Abdominal pain

    • Usually mild and constant in the right upper quadrant or epigastrium

    • Often aggravated by jarring or exertion

    • Rarely severe enough to simulate cholecystitis

  • Jaundice

    • Never develops in many patients

    • Occurs after 5–10 days but may appear at the same time as the initial symptoms

    • With its onset, prodromal symptoms often worsen, followed by progressive clinical improvement

    • Stools may be acholic

  • Hepatomegaly—rarely marked—is present in over 50% of cases; liver tenderness is usually present

  • Splenomegaly occurs in 15% of patients

  • Soft, enlarged lymph nodes—especially in the cervical or epitrochlear areas—may occur

  • The acute illness usually subsides over 2–3 weeks

  • Complete clinical and laboratory recovery by 9 weeks

  • Clinical, biochemical, and serologic recovery may be followed by one or two relapses, but recovery is the rule

  • A protracted course has been reported to be associated with HLA DRB1*1301

Differential Diagnosis

  • Other viruses that cause hepatitis, particularly hepatitis B and C viruses, as well as Epstein-Barr (infectious mononucleosis) virus, cytomegalovirus, herpes simplex virus, ...

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