Differential Diagnosis for HLH
- Single most likely diagnosis
- Familial Hemophagocytic Lymphohistiocytosis (FHL): This is a genetic disorder that affects the immune system, leading to an overactive and inappropriate immune response, which is a hallmark of HLH. The presence of a family history or early onset of symptoms increases the likelihood of this diagnosis.
- Other Likely diagnoses
- Secondary Hemophagocytic Lymphohistiocytosis (sHLH): This condition is triggered by infections, autoimmune disorders, or malignancies, leading to a similar immune dysregulation as seen in FHL. Recent infections, autoimmune symptoms, or a history of cancer could point towards this diagnosis.
- Macrophage Activation Syndrome (MAS): Often associated with systemic juvenile idiopathic arthritis, MAS presents with symptoms overlapping those of HLH, including fever, hepatosplenomegaly, and cytopenias. A history of autoimmune disease, particularly rheumatologic conditions, supports this diagnosis.
- Do Not Miss diagnoses
- Sepsis: Although sepsis is a distinct clinical entity, its presentation can overlap with HLH, especially in the context of a severe infection triggering an overwhelming immune response. Missing sepsis could be fatal due to the need for prompt antibiotic therapy.
- Malignancy: Certain cancers, like lymphomas or leukemias, can mimic or trigger HLH. Failing to diagnose an underlying malignancy could lead to delayed appropriate treatment and poor outcomes.
- Rare diagnoses
- Langerhans Cell Histiocytosis (LCH): A rare disorder characterized by the proliferation of Langerhans cells, which can lead to a variety of systemic symptoms, including those that overlap with HLH. The presence of characteristic skin rashes, bone lesions, or diabetes insipidus might suggest LCH.
- Rosai-Dorfman Disease: A rare histiocytic disorder that can present with lymphadenopathy and systemic symptoms, occasionally mimicking HLH. The diagnosis is often made after histopathological examination of lymph node biopsies.