Henoch-Schonlein Purpura (HSP)

Henoch-Schönlein purpura is an IgA-mediated, autoimmune, hypersensitivity vasculitis of childhood. The main clinical features are skin purpura, arthritis, abdominal pain, gastrointestinal bleeding, orchitis, and nephritis. The aetiology remains unknown.

• In the United Kingdom, the estimated annual incidence is 20 cases per 100,000 population.¹
• The peak prevalence is in children aged 3-10 years. It is rare in infants and young children.
• The disease occurs mostly in the Winter months and the male-to-female ratio is 1.5-2:1. Whites are more affected than blacks.

Risk Factors

Associated conditions preceding Henoch-Schönlein purpura include:

• Infections: e.g. Group A streptococci, Mycoplasma, Epstein-Barr virus
• Vaccinations
• Environmental exposures: e.g. drug and food allergens, pesticides, cold exposure, insect bites²

• In one half to two thirds of children, an upper respiratory tract infection precedes the clinical onset by 1-3 weeks.
• Generally, patients appear to be mildly ill, with low-grade fever.
• Symmetrical erythematous macular rash, especially on the back of the legs, buttocks, and ulnar side of the arms.
• Within 24 hours, the macules evolve into purpuric lesions, which may coalesce and resemble bruises.
• Abdominal pain and bloody diarrhoea may precede the typical purpuric rash. Intussusception should then be considered (occurs in 2-3% of patients). Henoch-Schönlein purpura may also cause nausea and vomiting.
• Arthralgias, especially knees and ankles. Joints may be swollen, tender, and painful but permanent deformity does not occur.
• Renal involvement:
  • Affects 50% of older children and 25% of children under 2 years of age.
  • Less than 1% of patients progress to end stage renal disease.
  • Usually occurs within 3 months of disease onset.
  • There is usually no relationship between the severity of nephritis and the extent of the other manifestations of Henoch-Schönlein purpura.
  • Microscopic haematuria with mild-to-moderate proteinuria may occur.
  • Nephrotic syndrome may also occur.
  • Oliguria and hypertension are rare.
• Scrotal involvement may mimic testicular torsion.
• Neurological: headaches may occur.

• Connective tissue diseases, e.g. SLE
• Other causes of purpuric rash, e.g. thrombocytopenia
• Other causes of glomerulonephritis
• Acute hemorrhagic oedema of infancy is milder and occurs in infants younger than 2 years. The onset is sudden, with acute palpable purpura, bruises, and tender oedema of the limbs and face.³

• Urinalysis: haematuria; may also be proteinuria
• Full blood count: may be raised white cell count with eosinophilia; normal or increased platelets
• Raised ESR
• Serum creatinine may be elevated in renal involvement
• Serum IgA levels are often increased
• Autoantibody screen: connective tissue diseases
• Abdominal ultrasound: if gastrointestinal symptoms - for diagnosis intestinal obstruction
• Barium enema: may be used to confirm and treat intussusception
• Testicular ultrasound: assessment of possible torsion
• Renal biopsy: if persistent nephrotic syndrome

• Henoch-Schönlein purpura is usually self-limiting and no form of therapy has been shown to appreciably shorten the duration of disease or prevent complications. Therefore treatment for most patients remains primarily supportive.
• Non-steroidal anti-inflammatory drugs may help joint pain but should be used with caution in patients with renal insufficiency.
• May require admission to hospital for monitoring of abdominal and renal complications.
• Nephropathy: treated supportively. A variety of drugs (steroids, azathioprine, cyclophosphamide) and plasmapheresis have been used to prevent the progression of the renal disease but the results of trials have been inconsistent.⁴
• Corticosteroids can ameliorate associated arthralgias and the symptoms associated with gastrointestinal dysfunction. There is no definitive evidence that corticosteroids affect the outcome of renal disease.
• No controlled clinical trials have been performed with immunosuppressive drugs, although azathioprine or cyclophosphamide may be beneficial.⁴
• Plasma exchange is used in the management of some adults with vasculitis and idiopathic rapidly progressive nephritis.⁴

• Renal involvement occurs in 50% of older children but is only serious in approximately 10% of patients. Overall, 2-5% of cases progress to end stage renal failure. The renal prognosis is worse in older children and adults.
• Other rare complications include myocardial infarction, pulmonary haemorrhage, pleural effusion, intussusception (in 2-3% of patients), gastrointestinal bleeding, bowel infarction, seizures, mononeuropathies.
• Recurrence of symptoms and recurrence renal impairment may occur but recurrence of renal impairment is rare.

• HSP is an acute self-limited illness and usually resolves without treatment, but may rarely lead to complications. Initial attacks of Henoch-Schonlein purpura can last several months. One third of patients have one or more recurrences.
• Children younger than 3 years have a shorter, milder course and fewer recurrences.
• The long-term prognosis of Henoch-Schönlein purpura is directly dependent on the severity of renal involvement.⁵