What is the likely diagnosis for a 7-year-old patient with aching joints, malaise, characteristic rash, gastrointestinal symptoms, and a recent history of upper respiratory infection (URI), presenting with petechiae, palpable purpura, and abdominal pain?

Henoch-Schönlein Purpura (IgA Vasculitis)

This 7-year-old has Henoch-Schönlein purpura (HSP), the most common childhood vasculitis, characterized by the classic tetrad of palpable purpura on dependent areas, arthritis/arthralgia, abdominal pain, and preceding upper respiratory infection. 1, 2

Clinical Diagnosis

The diagnosis is clinical and does not require laboratory confirmation in this presentation:

• Palpable purpura on legs, buttocks, and backs of arms (dependent distribution) is the hallmark finding 1, 3
• Joint involvement (tender knees and ankles) occurs in 82% of pediatric HSP cases 3
• Abdominal pain with nausea (colicky pattern) affects 54-58% of patients 3, 4
• Preceding URI (3 weeks ago) is the typical trigger, as HSP generally follows an upper respiratory tract illness 2
• Normal CBC, coagulation studies (PT/PTT), and urinalysis effectively exclude thrombocytopenia, coagulopathy, and other causes of purpura 1

The age (7 years, average 7.02 years) and male gender fit the typical demographic profile 3.

Key Differentiating Features

The normal platelet count and coagulation studies distinguish HSP from other purpuric conditions:

• Immune thrombocytopenic purpura would show thrombocytopenia 1
• Meningococcemia would present with fever, toxicity, and coagulopathy 5
• Rocky Mountain spotted fever typically has fever, headache, and different rash distribution (palms/soles initially) 5
• Kawasaki disease requires fever ≥5 days plus 4 of 5 specific criteria (conjunctivitis, oral changes, lymphadenopathy, extremity changes, polymorphous rash), which this patient lacks 5

Critical Management Priorities

Monitor for renal involvement, which determines long-term prognosis:

• 68% of renal involvement occurs in the first month after onset 3
• Check urinalysis and blood pressure weekly for the first month, then monthly for 6 months 3
• Isolated hematuria is the most common renal manifestation, but 22% develop moderate-to-severe nephritis 3
• The normal initial urinalysis does not exclude future renal involvement 3

Assess gastrointestinal complications urgently:

• Stool occult blood testing is essential when abdominal pain is present 4
• When stool occult blood is 3+ or 4+, imaging studies (abdominal ultrasound) are indicated to detect intussusception or perforation 4
• Intussusception occurs in a small percentage but requires immediate surgical evaluation 4
• Monitor vital signs closely, as massive GI bleeding with hypovolemic shock can occur 4

Treatment Approach

Most cases are self-limited and require only supportive care:

• Adequate hydration and pain management with acetaminophen or ibuprofen 1, 2
• Avoid NSAIDs if significant GI bleeding is present 4
• Corticosteroids are NOT routinely indicated for uncomplicated HSP 2
• Consider corticosteroids only for severe abdominal pain, significant GI bleeding, or severe joint symptoms 2

Recurrences occur in 15% of patients, typically within the first few months 3.

Common Pitfalls

• Do not dismiss the diagnosis because rash appeared after joint symptoms – the atypical form with arthritis preceding purpura occurs in 22% of cases 3
• Do not stop monitoring after initial normal urinalysis – renal involvement can develop weeks to months after onset 3
• Do not confuse HSP with acute bacterial sinusitis despite the preceding URI – the purpuric rash and joint involvement are not features of sinusitis complications 5
• Do not obtain imaging for uncomplicated cases – reserve ultrasound for suspected intussusception or perforation based on clinical severity and stool occult blood results 4