The differential diagnosis of purpura in children depends about two considerations: (1) Does the patient look ill? and (2) What is the platelet count?
Here’s how it goes:
|Sick||Low||Meningococcemia, Leukemia, DIC, Hemolytic-Uremic Syndrome (HUS)|
|Sick||Normal or High||(*) Viremia (e.g., EBV), Vasculitis (e.g., Mucocutaneous lymph node syndrome [Kawasaki])|
|Well||Low||Immune Thrombocytopenic Purpura (ITP), Wiscott-Aldrich, Aplastic anemia|
|Well-ish||Normal||Henoch–Schönlein purpura, Vomiting or coughing (if in SVC distribution)|
|(*) But still always consider meningococcemia in any sick child with purpura, with or without thrombocytopenia!|
|Reference: Oxford Handbook of Clinical Specialties, 9e (2013).|