Differential Diagnosis for 7-year-old Female with Bicytopenia, Transaminitis, Fever, Aphthous Mouth Ulcers, Rash, Increased LDH, and Ferritin

• Single Most Likely Diagnosis
  • Hemophagocytic Lymphohistiocytosis (HLH): This condition is characterized by an overactive and inappropriate immune response, leading to the activation and proliferation of lymphocytes and histiocytes, which can cause the symptoms and lab findings presented, including bicytopenia, transaminitis, fever, and significantly elevated ferritin and LDH levels.
• Other Likely Diagnoses
  • Systemic Juvenile Idiopathic Arthritis (sJIA): Presents with fever, rash, and can have significant laboratory abnormalities including elevated ferritin and LDH. Mouth ulcers and hepatosplenomegaly can also occur.
  • Autoimmune Lymphoproliferative Syndrome (ALPS): Characterized by lymphadenopathy, splenomegaly, and cytopenias due to autoimmune destruction of blood cells. Elevated LDH and ferritin can be seen, and some patients may present with mouth ulcers and rash.
• Do Not Miss Diagnoses
  • Leukemia/Lymphoma: Although less likely given the combination of symptoms, certain types of leukemia or lymphoma can present with bicytopenia, transaminitis, fever, and elevated LDH. Missing a diagnosis of malignancy could be catastrophic.
  • Sepsis: Infection can cause a wide range of symptoms including fever, rash, and organ dysfunction. Sepsis is a medical emergency and must be considered, especially in a child presenting with fever and multi-organ involvement.
• Rare Diagnoses
  • Macrophage Activation Syndrome (MAS) secondary to another autoimmune condition: While similar to HLH, MAS is often seen in the context of another rheumatologic condition like systemic lupus erythematosus (SLE) or rheumatoid arthritis. It presents with similar laboratory findings and clinical symptoms.
  • Pearson Syndrome: A rare mitochondrial disorder that can present with cytopenias, liver dysfunction, and other systemic symptoms. It's much less common and typically presents in early infancy, but could be considered in a differential diagnosis for a child with multi-system involvement and bicytopenia.