This is a vasculitis that most commonly occurs in children. It tends to only affect the small vessels, and typically presents with:
- Palpable purpura – red/purple discolorations in the skin, often on the extensor surfaces of the feet, legs, arms, or sometimes on the buttocks. The rash may initially resemble urtricaria, but later becomes palpable.
- GI disturbance – may include colicky abdominal pain, abdominal tenderness, melena – occurs in 50% of patients
- Arthritis – including swelling of the joints – occurs in about 75% of patients
- Glomerulonephritis – occurs in about 50% of patients
- RBC casts
- M:F ratio – 1.3 : 1
The result of deposition of IgA complexes in small arteries, and subsequent complement activation. The exact aetiology is unknown, but could be a bacterial, viral or environmental agent. Often follows a respiratory tract infection
- Renal lesions tend to be focal, segmental, proliferative glomerulonephritis
- PLATELETS are normal
Rashes typically occur over a period of days. There may be several sites that develop at different times.
- Often relapsing / remitting – with episodes lasting an average around 4 weeks
- About 20% of cases will result in end-stage renal failure
- Prognosis is better in children
Usually clinical, in children with the typical rash. Diagnosis can be confirmed with biopsy of the lesion, which will shows IgA deposition in the walls of small arteries.
Renal biopsy is advisable if signs of renal disease
Other signs include:
- Don’t forget to rule out any medications as a cause
Steroids are the mainstay of treatment, and provide symptomatic relief for joint pan / swelling, oedema and abdominal pain, but they do not affect disease outcome, and do not improve renal function.
- In severe renal disease, IV immunosuppressants may be considered (e.g. cyclophosphamide + prenisolone), but this is rarely needed
- GI bleed – can be massive and life threatening
- Chronic renal failure – 5% of patients
- Acute renal failure – rare
- Haemoptysis – rare