Rash and Foot Pain in a 4-year-old Boy: What's Your Diagnosis?
Patient history. A 4-year-old boy is seen for a concerning rash; his father says the eruption was preceded by one week of intermittent, generalized leg discomfort that grew worse today and became constant, particularly in the ankles. The boy's mother noticed the rash when she checked his feet earlier in the day.
Vitals and examination. Vital signs were normal; mild bilateral leg edema was seen on physical examination and legs were cooler to the touch than expected.
Initial diagnostic testing. CBC normal, except for WBC 16x109/L; platelets, PT and PTT, and blood chemistries, normal.
Impressions, next steps. What is your impression, based on the image, above? What should you do next?
Diagnosis: Henoch-Schönlein purpura. HSP is an uncommon vasculitis of unknown etiology. It is often precipitated by a viral infection and typically occurs in winter/spring months, more commonlhy in children. Clinical presentation always involves a dependent, purpuric rash that may occur late. Also common are abdominal pain and arthralgias in the lower extremities.
HSP testing and treatment. Common findings include microscopic hematuria, hemoccult positive stool, proteinuria, and elevated inflammatory markers. Platelets and coagulation studies are typically normal. Rare complications include Intussusception, bowel perforation/significant GI bleeding; glomerulonephritis, seizures or intracranial bleeding. Treatment is supportive; admission if complications.