clinical features

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Symptoms do not occur in all people.

  • children <5 years - 80-95% of infections are asymptomatic
  • in adults - 70-95% of infections result in clinical illness
  • severity of symptoms also increases with age (1)

The course of acute hepatitis A can be typically divided into four clinical phases (2):

  • incubation phase or pre clinical period (during which time the virus replicates in the liver and is shed into the faeces)
    • average incubation period is 28 days (range of 15-50 days) (1)
    • patient is asymptomatic but transmissibility is of greatest concern (2)
  • prodromal or pre-icteric phase
    • may last from several days to couple of weeks
    • typically, there are non-specific flu like symptoms (malaise, myalgia, fatigue) and mild fever. There can be non-specific gastrointestinal symptoms like loss of appetite, fatigue, abdominal pain, nausea and vomiting
    • other symptoms like cough, pharyngitis, constipation, diarrhoea (3)
  • icteric phase
    • jaundice develops (with associated anorexia, nausea and fatigue)
    • usually lasts 1-3 weeks, in a minority of patients with cholestatic symptoms (itching and deep jaundice) - may last for 12 or more weeks (4)
    • dark urine and pale stools (before onset of jaundice)
    • tender hepatomegaly (4)
    • pruritus
    • fever is not present during this phase (4)
    • fulminant hepatitis may occur rarely (<1%) (1,2)
  • convalescent period
    • resolution of the disease occurs (2)
    • malaise, tenderness and minor abnormalities of hepatic function may persist

The hepatitis is usually mild. In children, it is frequently, sub-clinical. Adults tend to experience more serious and prolonged disease.

Faecal excretion of the virus declines once infection becomes asymptomatic.


Last reviewed 01/2018