Differential Diagnosis for a 5-year-old with Abdominal Pain, Intussusception, Hives, Facial Swelling, and Redness of Fingers and Toes

• Single Most Likely Diagnosis
  • Henoch-Schönlein Purpura (HSP): This condition is characterized by abdominal pain, intussusception, hives (purpura), and joint pain, which aligns with the symptoms described. The presence of intussusception, a known complication of HSP, further supports this diagnosis.
• Other Likely Diagnoses
  • Allergic Reaction or Anaphylaxis: The combination of hives, facial swelling, and redness of extremities could indicate a severe allergic reaction. However, the presence of intussusception is less commonly associated with anaphylaxis.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause abdominal pain and potentially intussusception, though the acute onset of hives and facial swelling is less typical.
• Do Not Miss Diagnoses
  • Sepsis: Although less likely given the specific constellation of symptoms, sepsis can cause a wide range of symptoms including abdominal pain, rash, and peripheral vasodilation leading to redness. It is critical to consider due to its high mortality if untreated.
  • Acute Abdominal Conditions (e.g., Appendicitis, Mesenteric Lymphadenitis): These conditions can cause severe abdominal pain and potentially mimic some of the symptoms, especially if there's an associated allergic reaction or other complicating factors.
• Rare Diagnoses
  • Systemic Vasculitis (e.g., Kawasaki Disease, Polyarteritis Nodosa): These conditions can present with a wide range of symptoms including rash, abdominal pain, and peripheral manifestations. However, they are less common and would typically have additional distinguishing features.
  • Autoimmune Enteropathy: A rare condition characterized by immune-mediated damage to the small intestine, which could potentially explain some of the gastrointestinal symptoms, though it's a less likely explanation for the full spectrum of symptoms described.