Variant forms of autoimmune hepatitis.

Variant forms of autoimmune hepatitis have features that are intermixed with another disorder (overlap syndrome) or findings that are inconsistent with or insufficient for a confident diagnosis of classic disease (outlier syndrome). Diagnostic criteria have not been codified, but application of a modified scoring system provides a template that can be combined with clinical findings to ensure uniform evaluation and classification. Variant forms are frequently assimilated into conventional diagnostic categories. and they may distort analyses of natural history and outcome. Management strategies are empiric, based on an assessment of the predominant characteristics and institution of the most appropriate drug regimen. Patients with variant syndromes who respond to corticosteroids typically have serum alkaline phosphatase levels of less than twofold the upper limit of normal at presentation. By distinguishing between these syndromes, further insights into natural history, genetic predisposition, and immunopathic mechanisms are possible.