Differential Diagnosis for Mixed Hepatocellular Liver Injury with an Urticarial Rash

Single Most Likely Diagnosis

• Autoimmune Hepatitis: This condition often presents with a mix of hepatocellular injury and can be associated with various autoimmune phenomena, including skin rashes like urticaria. The presence of autoantibodies and elevated IgG levels supports this diagnosis.

Other Likely Diagnoses

• Drug-Induced Liver Injury (DILI): Many drugs can cause hepatocellular injury and are also known to induce allergic reactions, including urticarial rashes. A thorough medication history is crucial for diagnosing DILI.
• Viral Hepatitis: Certain viral hepatitis infections, such as hepatitis B and C, can cause mixed hepatocellular injury. While less commonly associated with urticarial rashes, these infections can lead to extrahepatic manifestations, including skin rashes.
• Primary Biliary Cholangitis (PBC): Although primarily a cholestatic disease, PBC can have a mixed presentation and is associated with various autoimmune phenomena, including urticarial rashes.

Do Not Miss Diagnoses

• Wilson's Disease: This genetic disorder leads to copper accumulation in the liver and can cause mixed hepatocellular injury. While less commonly associated with urticarial rashes, missing this diagnosis can lead to severe and irreversible liver damage.
• Alpha-1 Antitrypsin Deficiency: This genetic disorder can cause liver disease and, in some cases, may be associated with skin manifestations, including rashes. It's crucial not to miss this diagnosis due to its implications for lung disease and the potential for liver transplantation.
• Budd-Chiari Syndrome: Although primarily a vascular issue, Budd-Chiari syndrome can cause liver injury and, in rare cases, may be associated with skin manifestations due to underlying conditions like polycythemia vera or other thrombophilic states.

Rare Diagnoses

• Erythema Multiforme with Hepatic Involvement: A rare condition characterized by skin lesions (including urticarial rashes) and can be associated with hepatitis.
• Hepatic Sarcoidosis: Sarcoidosis can affect the liver, causing mixed hepatocellular injury, and is also known to cause skin rashes, including urticaria, although this is less common.
• Mastocytosis: A condition involving mast cell proliferation can lead to liver injury and skin manifestations, including urticarial rashes, due to the release of histamine and other mediators.