An 8-year-old girl presents with bilateral ankle pain, a purpuric/petechial rash on her legs, and swelling of her feet. She has no fever. She reports having had rhinorrhea a week ago. Laboratory tests show a normal CBC, and Lyme and ASO titers are negative. She has mild hematuria and no proteinuria.
What is the diagnosis?
A. Post-streptococcal arthritis.
B. Lyme disease.
C. Systemic lupus erythematosus.
D. Henoch-Schönlein purpura.
E. Immune thrombocytopenia.
The correct answer is “D.” Henoch-Schönlein purpura (HSP), or IgA vasculitis, causes a characteristic rash (nonthrombocytopenic palpable purpura); arthritis or arthralgias, or both; colicky abdominal pain; and renal disease. The history of a recent upper respiratory tract infection is classic for HSP. For the diagnosis to be HSP, the platelet count and coagulation studies must be normal. (See Table 7–4 and Figure 7–3.) Patients with lupus usually present with an abnormal CBC, indicating leukopenia, thrombocytopenia, anemia, or a combination of these. The patient’s Lyme titer is negative, and Lyme arthritis tends to be in the knees. This is unlikely streptococcal disease as the patient’s ASO titer is negative, she has no history of pharyngitis, and it would not explain the rash. Her platelet count is normal, ruling out immune thrombocytopenia.
Photo: Kline MW. Rudolph's Pediatrics, 23e; 2018.