Henoch-Schönlein purpura (HSP)

• Background
  • HSP is the most common vasculitis of childhood. 
  • It is most commonly seen in children 2-8 years of age. 
  • In ~50% of cases there is a history of a recent upper respiratory tract infection 
• Assessment
  • Purpura:
    • If atypical distribution or the child is unwell, consider meningococcaemia, thrombocytopenia, or other rare vasculitides.
  • arthritis/arthralgia (~50-75%):
    • Swelling and arthralgia of large joints are often the patient’s main complaint. In most situations this pain resolves spontaneously within 24-48 hours.
  • Abdominal pain (~50%) 
    • Uncomplicated abdominal pain often resolves spontaneously within 72 hours. 
    • However serious abdominal complications may occur including
      • Intussusception
      • bloody stools
      • haematemesis
      • spontaneous bowel perforation
      • pancreatitis.
  • renal involvement (~25-50%) (haematuria/proteinuria)
    • Haematuria is present in 90% of cases, but only 5% are persistent or recurrent. 
    • Less common renal manifestations include
      • Proteinuria
      • nephrotic syndrome
      • isolated hypertension
      • renal insufficiency
      • renal failure (<1%).
  • hypertension
  • Subcutaneous oedema (scrotum, hands, feet, sacrum): This can be very painful.
  • Rare complications – pulmonary and CNS involvement

Examination	Assess for	Features
Vitals	Hypertension
Skin	Palpable purpura, petechiae and ecchymoses	Usually symmetrical Gravity/pressure-dependent areas (buttocks and lower limbs in ambulatory children)
	Painful subcutaneous oedema	Periorbital area Dependent areas (hands, feet, scrotum)
Joints	Arthritis/arthralgia	Usually affects large joints of lower limbs Occasionally upper limbs Usually no significant effusion or warmth
Abdominal	Signs of bowel obstruction Peritonism Gastrointestinal haemorrhage Exclude testicular torsion if presents with significant groin pain	Most common complication is intussussception Others – GI haemorrhage, bowel ischaemia, necrosis or perforation, protein-losing enteropathy and pancreatitis
Respiratory	Respiratory distress	Diffuse alveolar haemorrhage
Neurological	Changes in mental status	Labile mood, apathy, hyperactivity, encephalopathy
	Focal neurological signs	Consider intracranial haemorrhage
Urinalysis	Macroscopic haematuria Proteinuria (more than trace on urinalysis)	Proteinuria/haematuria, nephrotic syndrome, acute nephritic syndrome, hypertension, renal impairment and in some, renal failure

Typical rash distribution  

Investigations 

• Urinalysis
  • usually the only investigation needed in a classic presentation of HSP 
  • If there is hypertension, macroscopic haematuria or significant proteinuria:
    • Formal urine microscopy and urinary protein-creatinine ratio (UPCR)
    • Bloods for urea/electrolytes/creatinine (UEC) and albumin
• rule out differentials if the diagnosis is unclear eg ITP, leukaemia, or to identify potential complications of HSP. These may include:
  • FBE, UEC, albumin
  • Blood and urine culture
  • Abdominal imaging
  • ANA, dsDNA, ANCA, C3/C4 if significant renal involvement with an unclear diagnosis 

Acute Management 

• subcutaneous oedema
  • bed rest and elevation of the affected area.
• Mild Pain
  • Regular paracetamol +/- a short course of NSAIDs such as ibuprofen (10 mg/kg TDS) or naproxen (10 mg/kg BD) can be used if not otherwise contraindicated  
• Moderate-severe pain
  •  The use of steroids (glucocorticoids) has been shown to reduce the duration of abdominal and joint pain. 
  • steroids do not impact the rate of long term renal complications of HSP. Oral prednisolone 1-2 mg/kg/day (maximum 60 mg/day) or IV methylprednisolone 0.8-1.6 mg/kg/day (maximum 1g/day) can be used while symptoms persist. 
• Indications for Admission
  • Serious abdominal complications
  • Severe debilitating pain
  • Severe renal involvement (see ‘discussion with Nephrology’ under ‘Follow-Up’ below)
  • Neurological involvement
• Prognosis
  • A first episode of HSP, in the absence of significant renal disease, usually resolves within 4 weeks. The rash is usually the last symptom to remit.
  • Joint pain usually resolves spontaneously within 72 hours
  • Uncomplicated abdominal pain usually resolves spontaneously within 24-48 hours
• Follow-Up
  • Regular GP or paediatrician review is critical to identify subsequent renal involvement which rarely requires a renal biopsy +/- immunosuppression
  • If the initial urinalysis is normal or only reveals microscopic haematuria, review clinically and check BP/early morning urinalysis at these recommended time intervals:
  • Weekly for the first month after disease onset
  • Fortnightly from weeks 5-12
  • Single reviews at 6 and 12 months

	Kawasaki disease	Henoch-Schönlein purpura
Etiology:	Idiopathic Vasculitis Affects small and medium sized vessels	Acute immune complex-mediated, small vessel Leukocytoclastic Vasculitis and Idiopathic inflammatory IgA Hypersensitivity
Age of onset:	It primarily affects children under the age of 5 peak incidence: 6 months – 2 years	common : 2 – 11 can occur in individuals of any age, including adults.
Clinical features:	Fever for 5 days or more Polymorphous skin eruption on trunk (80-96%) May appear maculopapular, or Erythema Multiforme-like Conjunctivitis (84-89%%) Acute Lymphadenopathy Edema or induration of hands and feet (65%) Red palms and soles (69%) –  Sharp demarcation at ankles and wrists Strawberry Tongue  Diffuse reddening of the oropharynx	palpable purpura that typically occurs on the buttocks and lower extremities.  abdominal pain joint pain/swelling Hematuria Proteinuria Onset over days to weeks (following Upper Respiratory Infection in most cases) Duration: 4-6 weeks Symptoms may recurr in up to one third of patients (ultimately resolves within 4 to 6 months)
Organ involvement:	Urethritis with sterile pyuria (75%) Polyarthralgia Aseptic Meningitis (25%) Abdominal Pain and Diarrhea (25%) Obstructive Jaundice with acute gallbladder hydrops Cardiac Disease (20%) Pericardial Effusion Congestive Heart Failure Arrhythmias (e.g. Tachycardia) Valvular dysfunction (25%) Mitral Regurgitation (most common) Aortic root dilatation Coronary Artery aneurysm	Gastrointestinal Bleeding Glomerulonephritis Cardiopulmonary conditions Hypertension Myocardial Infarction Pulmonary Hemorrhage Pleural Effusion Gastrointestinal conditions Bowel infarction Pancreatitis Gallbladder Hydrops Protein Losing Enteropathy Behavior Changes Seizures Mononeuropathy Intracranial Hemorrhage Renal disorders (2-20%) Hematuria Proteinuria (Nephrotic Syndrome may be present)
Prognosis:	If promptly diagnosed and treated with intravenous immunoglobulin and aspirin, the prognosis for Kawasaki disease is generally good	Most cases of HSP resolve on their own without long-term complications. However, in some instances, renal involvement can lead to persistent kidney problems, including nephrotic syndrome or chronic kidney disease