Abstract: The outbreak of acute severe hepatitis of unknown aetiology in children has been reported in many European countrie,the main clinical manifestations of this disease are significant elevation of aminotransferase, alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >500 U/L, often accompanied by jaundice, and hepatomegaly. Most children have gastrointestinal symptoms. Some cases have fever or respiratory symptoms, and a small number of cases develop acute liver failure. No related cases have been reported in China. At present, its etiology is still not completely clear, and adenovirus infection is still considered as the most likely main cause. However, the possibility that SARS-CoV-2 is involved cannot be ruled out. The immune activation mediated by SARS-CoV-2 superantigen may be related to the occurrence of severe hepatitis of unknown origin in children. At present, the main clinical treatment is symptomatic and supportive treatment. A small number of children have acute liver failure, and some of them need liver transplantation. To strengthen the knowledge and understanding of acute hepatitis of unknown origin in children, and provide theoretical guidance and reference for the development of clinical diagnosis, treatment and health prevention and control policies.

Key words: Unknown aetiology, Children, Severe acute hepatitis