Differential Diagnosis for Rash after AKI and Elevated Liver Function Tests

• Single most likely diagnosis
  • Acute viral hepatitis: This is a likely diagnosis given the combination of rash, acute kidney injury (AKI), and elevated liver function tests. Viral hepatitis can cause a rash, and some forms like hepatitis B can lead to extrahepatic manifestations including kidney injury.
• Other Likely diagnoses
  • Drug-induced liver injury (DILI) with rash: Many medications can cause liver injury and a rash. Given the context of AKI and elevated liver enzymes, a drug that affects both liver and kidney function should be considered.
  • Autoimmune hepatitis: This condition can present with a rash, elevated liver enzymes, and potentially affect kidney function, although the latter is less common.
  • Wilson's disease: Although rare, Wilson's disease can cause liver dysfunction, kidney injury, and sometimes a rash, making it a consideration in younger patients.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Hemolytic-uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP): These conditions can cause AKI and have a petechial rash. They are life-threatening and require immediate intervention.
  • Malignancy (e.g., lymphoma): Certain malignancies can cause both liver and kidney dysfunction and may present with a rash. Missing a diagnosis of malignancy could have severe consequences.
• Rare diagnoses
  • Porphyria cutanea tarda: A disorder that can cause a rash, liver enzyme elevations, and potentially AKI, although the latter is less common.
  • Erythema multiforme major (or Stevens-Johnson syndrome): These are severe skin and mucous membrane disorders that can be associated with hepatitis and AKI in rare cases.
  • Leptospirosis: A zoonotic infection that can cause liver and kidney dysfunction along with a rash, more common in individuals with exposure to contaminated water.