Primary biliary cholangitis (PBC) is a chronic progressive cholestatic liver disease of uncertain etiology. Although PBC is frequently complicated by Sjögren's syndrome and chronic thyroiditis, it can also be associated with a variety of other autoimmune disorders. We herein describe a rare case of immune thrombocytopenic purpura (ITP) coexistence with PBC and localized cutaneous systemic sclerosis (LcSSc). A 47-year-old woman with PBC and LcSSc who was positive for antiphospholipid antibody experienced a rapid decrease in platelet count to 1.8 × 104/µL during follow-up. After clinical findings ruled out thrombocytopenia from cirrhosis, a diagnosis of ITP was made following bone marrow examination. Her human leukocyte antigen (HLA) type was HLA-DPB1*05:01, which has been associated with disease susceptibility to PBC and LcSSc, but not to ITP. A careful review of similar reports suggested that in PBC, other collagen disease complications, positive antinuclear antibody, and positive antiphospholipid antibody may all support a diagnosis of ITP. Clinicians should be vigilant for ITP when rapid thrombocytopenia is observed during the course of PBC.
Keywords: Immune thrombocytopenic purpura (ITP); Localized cutaneous systemic sclerosis (LcSSc); Primary biliary cholangitis (PBC); Systemic sclerosis (SSc).
© 2023. Japanese Society of Gastroenterology.