Differential Diagnosis for Hemorrhagic Bullous Lesions and Purpuric Lesions

Given the complex presentation of hemorrhagic bullous lesions at palms, purpuric lesions at other sites, ecchymotic lesions at both lower limbs with cyanosis, arthralgia, fatigue, lethargy, fever, vomiting, diarrhea, and the recent history of receiving vaccines including the meningococcal vaccine, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Vasculitis (e.g., Henoch-Schönlein Purpura or Leukocytoclastic Vasculitis): The presence of purpuric lesions, arthralgia, and the recent vaccination history could suggest an immune-mediated vasculitis. The initial thrombocytopenia and subsequent normalization, along with elevated WBCs and neutrophilia, support an inflammatory process.

• Other Likely Diagnoses

  • Immune Thrombocytopenic Purpura (ITP): Although the platelet count normalized, the initial thrombocytopenia and purpuric lesions could suggest ITP, potentially triggered by the vaccine.
  • Infectious Vasculitis or Sepsis: Despite negative bacterial blood cultures, the clinical presentation of fever, vomiting, diarrhea, and the initial diagnosis of purpuric eruption secondary to sepsis and disseminated intravascular coagulopathy (DIC) suggest that an infectious cause cannot be entirely ruled out without further investigation.
  • Drug Reaction (including vaccine reaction): The temporal relationship between vaccine administration and the onset of symptoms suggests a possible drug or vaccine reaction, which could manifest as a cutaneous adverse event.

• Do Not Miss Diagnoses

  • Meningococcemia: Given the recent meningococcal vaccination, it's crucial to consider meningococcemia, especially with symptoms like fever, vomiting, diarrhea, and purpuric lesions, which can be indicative of this potentially life-threatening condition.
  • Thrombotic Thrombocytopenic Purpura (TTP): Although less common, TTP is a critical diagnosis to consider due to its severe prognosis and the presence of thrombocytopenia, fever, and neurological symptoms (fatigue, lethargy).
  • Disseminated Intravascular Coagulation (DIC): The initial diagnosis of DIC, along with the clinical presentation, warrants careful consideration and monitoring, as DIC can be life-threatening and requires prompt management.

• Rare Diagnoses

  • Ehlers-Danlos Syndrome with associated vascular fragility: Although rare, this condition could explain the hemorrhagic bullous lesions and ecchymotic lesions, especially if there's a family history or other suggestive features.
  • Autoimmune Lymphoproliferative Syndrome (ALPS): This rare condition can present with lymphadenopathy, splenomegaly, and cytopenias, including thrombocytopenia, and could be considered if other diagnoses are ruled out.
  • Atypical Hemolytic Uremic Syndrome (aHUS): Characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury, aHUS is a rare but critical diagnosis to consider, especially with the presence of thrombocytopenia and systemic symptoms.