Autoimmune hepatitis (AIH) is a chronic, relapsing and remitting, immune mediated liver disease which progresses to cirrhosis if left untreated. A significant number of patients may present with acute hepatitis or acute liver failure, which are often misdiagnosed as toxic liver injury. AIH shows a preponderance for young women but may be seen in children and elderly. Diagnosis requires integration of clinical, biochemical and serologic parameters along with supportive liver histology and exclusion of other causes of liver disease. Liver biopsy is a pre-requisite for diagnosis of AIH, to assess severity and stage of disease, exclude other entities and recognize any concurrent morbidities. No single biomarker or histologic feature is pathognomonic for AIH. The diagnostic and histologic criteria have undergone several modifications since the Original Scoring system proposed by the International Autoimmune Hepatitis Group (IAIHG) in 1993. Recently, IAIHG has proposed consensus recommendations for histologic criteria, relevant for both acute and chronic AIH.
This review article will describe the evolving diagnostic criteria for AIH with their limitations and utility, with an emphasis on the role of liver histology in diagnosis and management of AIH.