Immunoglobulin A vasculitis (IgAV), formerly called Henoch-Schönlein purpura, is a necrotizing small-vessel vasculitis of unknown etiology that is the most common form of vasculitis in children aged younger than 10 years. It is characterized by IgA-immune complex and C3 and fibrin deposition in small vessels: primarily capillaries, postcapillary venules, and occasionally arterioles in affected organs. The annual incidence in childhood is 3-26 per 100 000. It is seen more frequently in males, White individuals, and those of Asian descent, commonly during fall and winter seasons. Episodes can often be preceded by an upper respiratory infection.
IgAV is characterized clinically by palpable purpura, abdominal pain, arthritis, and hematuria. Children are more likely to have fevers and abdominal pain. There are prodromal symptoms of malaise, headache, and arthralgias. An individual episode may persist for 3-6 weeks, with recurrences in many patients.
Almost all patients develop palpable purpura. Other skin involvement may include petechiae, bullae, edema, and necrosis. Infants' skin involvement is sometimes limited to the face or arms. Joint abnormalities are the second most common symptom and may accompany skin eruptions with severe pain and sometimes swelling, warmth, and tenderness. Ankles and knees are most often involved; symptoms are often transient and migratory.
Severe abdominal pain, vomiting, hematemesis, diarrhea, and hematochezia occur in about 50% of children. An involved inflamed and edematous bowel may be accompanied by appendicitis, ileus, and infarction. Intussusception and bowel perforation are more common in children than in adults.
Renal involvement occurs in 20%-50% of children and is usually self-limited, with only 1%-3% of patients progressing to end-stage renal disease. Risk factors for more severe renal disease include increased age at presentation, increased levels of serum IgA, and baseline nephritic or nephrotic disease. Notably, skin lesions above the waist may indicate higher risk in adults, but studies have not shown this in children.
ICD10CM: D69.0 – Allergic purpura
SNOMEDCT: 191306005 – Henoch-Schönlein purpura
Differential Diagnosis & Pitfalls
Other small vessel vasculitides – Causes include infections, drugs, connective tissue diseases, and malignancies.
Gianotti-Crosti syndrome (papular acrodermatitis of childhood) – Lesions are primarily exanthematous and papular, but lesions on the lower legs can be purpuric; also occurs after viral infection.
Acute hemorrhagic edema of infancy – Occurs in younger children, facial involvement is common, trunk is usually spared, children are well-appearing and less likely to have systemic symptoms.
Erythema multiforme – Presents with erythematous, targetoid plaques most commonly acrally distributed.
Connective tissue diseases – Have associated photosensitivity, additional antibody abnormalities, and are unlikely to be self-limited.
Meningococcemia – May result in purpura fulminans characterized by necrotic, nonblanchable palpable purpura on predominantly acral areas; patients are more ill.
Rickettsial infections – Have characteristic purpura on the hands and feet, and patients are systemically ill.
Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.