Henoch-Schonlein purpura
Background
- Any child with a rash, abdominal pain and arthritis/arthralgia should have HSP considered as a diagnosis.
- IgA complex mediated small vessel vasculitis
- Any age (majority from 2-8 years)
- M:F=2:1
Initial clinical assessment
- Airway, Breathing, Circulation – HR, BP, CRT, Temperature
- Full CVS, chest and abdominal examination
- Examination of all joints for pain and/or swelling
- Urine dipstick
Clinical manifestations
- Onset may be acute or (50%) chronic have malaise and low grade fever
- Skin lesions:
- Always present but extremely variable presentations
- Classically on lower extremities and buttocks on the extensor surfaces, but can affect upper extremities, face and trunk.
- Classic lesions are reddish/purple in colour, slightly raised and palpable (erythematous maculopapules). They initially blanch on pressure but can become purpuric or petechial
- Purpuric areas change from red to purple to fading
- They may appear in crops and a variety may occur at any time
- Various patterns of erythema multiforme and erythema nodosum may rarely occur
- Arthritis:
- Approximately 2/3 of affected children
- Large joints, especially knees and ankles are most commonly affected
- It is transient and non-migratory
- Children present with swollen, tender, painful joints
- Joint effusions are serous not haemorrhagic
- Arthritis generally resolves in a few days with no residual deformity or joint damage.
- It may recur in periods of active disease
- GI symptoms:
- Approximately 2/3 of children affected
- GI symptoms occur before the rash in 25% of children.
- Colicky abdominal pain (98%), with or without vomiting.
- Gut wall oedema & haemorrhage may result in gross or occult blood per rectum
- Upper GI haemorrhage (5%) and intussusception or obstruction are rare
- Renal involvement:
- 40-50% of children in the acute phase, with some degree of renal insufficiency in 5% and chronic renal failure in up to 1.5%.
- Casts or proteinuria may occur in the first few weeks or can appear later after the other manifestations have settled.
- 20-30% of children may have gross haematuria.
- Occasionally moderate hypertension, oliguria and more rarely, hypertensive encephalopathy, may occur.
- Those that develop chronic renal disease do so within a few years of the acute phase of HSP
- Signs of renal involvement may take up to 3 months to develop. If they are not there by 3/12 they are unlikely to develop.
- Renal involvement may be present in patients with or without haematuria. it is more likely in children with haematuria or a persistent rash.
- CNS involvement:
- Rare but potentially serious complications such as seizures, paresis and coma may occur.
- Other manifestations:
- Hepatosplenomegaly and lymphadenopathy during the acute phase
- Testicular swelling, pain (orchitis or necrosis) and haemorrhage
- Intramuscular haemorrhage
- Rheumatoid like nodules
- Cardiac involvement
- Eye involvement
Diagnosis
Any child with a rash, abdominal pain and arthritis/arthralgia should have HSP considered.
Differential diagnoses
- (Excluded from history and examination findings)
- Meningococcal septicaemia
- Thrombocytopenia
- Viral exanthem
- Septic arthritis
- Rarely systemic vasculitides – Wegeners, SLE, hypersensitivity vasculitis, polyarteritis nodosa
Investigations
There are no diagnostic tests
- Urine microscopy – RBC, WBC, casts, or albumin
- Weight and height
- BP
- In those with proteinuria/macroscopic haematuria:
- FBC (eosinophilia, normal platelet count)
- Clotting (normal)
- U&E, creatinine, bone profile
- Early Morning Urine protein/creatinine ratio
- Consider: Stool sample for microscopy or occult blood if infective cause for PR bleeding is a possibility.
- Additional investigations:
- ASOT titre/Anti DNA’ase B titres and throat swab to exclude streptococcal infection
- Complement C3, 4
- Autoimmune profile
- pANCA, cANCA
- Renal USS
Treatment
There is no specific therapy
- Supportive: hydration, nutrition, electrolyte balance.
- If allergens are proven then they should be avoided or treated e.g. streptococcal infection.
- Simple analgesia. Use NSAIDs with caution
- With severe abdominal pain, arthritis, pulmonary haemorrhage consider prednisolone
- With severe skin manifestations discuss the use of colchicine or dapsone
Hypertensive = BP > 97th centile on one
reading, or > 90th centile on 3 readings.
Prognosis
- Microscopic haematuria without proteinuria generally has a benign course.
- Isolated microscopic haematuria/mild proteinuria have a good prognosis, with often only mild histological changes.
- < 5% develop CRF, <5% ESRD in 10-25 years.
- Increasing proteinuria or the development of nephrotic syndrome or renal insufficiency are indicators of severe disease.
- Of those that develop acute nephritic/nephrotic syndrome, 20% progress to ESRD, 44-50% develop hypertension, abnormal renal function or CRF.
- Chronic renal disease may occur in approx 1% of patients.
- 25% of children with renal disease may have persistence of urine sediment for several years.
- Haematuria at the onset of the disease or renal manifestations within the first 3 months after the onset of disease were significantly more common in one group of children with renal sequelae at one year follow-up.
