Henoch Schonlein Purpura is an IgA mediated vasculitis and it is the most common vasculitis seen in paediatrics.
The aetiology is unknown but it often follows on from an upper respiratory tract / non specific viral infection.
The peak age of onset is 4-6 years old.
Incidence is 10-20 per 100,000 children per year in the UK.
Contents
Pathophysiology
Group A strep, Epstein-Barr virus, Coxsackievirus, mycoplasma, hepatitis A and B, parvovirus B19, campylobacter and adenoviruses, and vaccines, have all been previously reported as triggers for HSP.
IgA immune complexes are deposited in small blood vessels in the skin, joints, kidneys, and gastrointestinal tract which causes inflammation.
Presentation
Presents as palpable purpura with any of the following:
- Abdominal pain
- Bloody diarrhoea
- Joint pain
- Nephritis causing proteinuria +/- haematuria
- Scrotal pain and swelling
Systems Involved
Skin
Symmetrical palpable purpuric rash on extensor surfaces of lower limbs and in pressure dependent areas.
The rash usually starts out as red spots or raised lumps and very quickly this progresses to palpable purpura over the lower legs, buttocks and knees. Can also occur on upper limbs but this is more rare. Occasionally blisters / ulcers can develop. (T, 2023)


A typical HSP rash to the lower limbs


Bilateral lower limb purpura seen in HSP with ankle swelling present


An image demonstrating how the rash can appear slightly lighter with smaller purpura


A purpuric rash in HSP seen on darker skin

Purpric lower limb rash in HSP seen on darker skin
Gastrointestinal Tract
GI manifestations of HSP occur due to submucosal haemorrhages and capillary haemorrhage which causes fluid accumulation in the bowel wall. The small bowel is most affected.
GI involvement causes the following symptoms: abdominal pain (85%), vomiting (40%), GI bleeding (66%), massive lower GI bleed (20%) and diarrhoea (20%). Occasionally abdominal pain can be the presenting symptoms of HSP. (Khader Y, 2021)
Occasionally children with HSP can present with intussusception (3-4%) as the vasculitis acts as a lead point for the bowel invagination.
Joints
The incidence of joint involvement in HSP is up to 78% and 15% of children with HSP present with joint pain / swelling as the initial symptom.
Joint involvement includes arthritis and arthralgia and most of those with joint involvement have swelling. Pain can be migratory and recurrent. Joints involved can be unilateral or bilateral and are commonly the knees, ankles, hands and feet. (Wang X, 2016)
Kidneys
Around 30-50% of patients have evidence of renal involvement with HSP. 1-2% of these children progress to end stage renal failure.
Renal involvement can present as proteinuria, and/or microscopic or macroscopic haematuria, with more severely affected children presenting with nephritis and hypertension.
All other organ involvement in HSP is usually self-limiting and mild but HSP nephritis can evolve into end stage renal disease requiring dialysis and renal transplant
Several studies have demonstrated that a risk factor for renal involvement in HSP is increased age at diagnosis. (Kim WK, 2021)
Urogenital tract
It is rare to find scrotal involvement in HSP but cases do occur, presenting as acute testicular pain (mimicking testicular torsion), epididymitis and orchitis. Symptoms include scrotal pain and tenderness, erythema and swelling. (Dalpiaz A, 2015)
Differentials:
- Connective tissues disease, e.g. Systemic Lupus Erythematosus (rashes, joint pains and swelling, renal involvement)
- Idiopathic Thrombocytopaenic Purpura (Isolated low platelets following a viral infection, usually presents with nose bleeds and a non-blanching rash)
- Meningococcal sepsis (presents with fever, widespread non-blanching purpura, these children deteriorate very quickly with sepsis)
- Inflammatory Bowel Disease (presents with abdominal pain, bloody diarrhoea, also these children are prone to juvenile arthritis and eye involvement including uveitis)
Investigations:
HSP is a clinical diagnosis but there are a list of investigations that should be performed to rule out certain differentials and to look for complications. These include:
- Blood pressure
- Urine dip to look for proteinuria / haematuria
- Bloods for FBC, U&Es, coagulation, LFTs and bone profile. Include a CRP if there is any history of fever in the context of a non blanching rash)
- If there are signs of renal involvement such as haematuria or hypertension then further bloods should be done including an ASOT, DNAase B, complement 3 and 4.
Management
HSP is usually benign and self limiting and resolves without medical treatment within 6 weeks. Any intervention or treatment is usually supportive, e.g. analgesics
If there is joint pain / swelling ensure the child is taking regular paracetamol and (if renal function is normal and there is no evidence of GI haemorrhage) ibuprofen to control pain.
If there is severe abdominal pain, GI haemorrhage or acute painful testicular swelling ask for an urgent surgical review.
Children with any of the following should be discussed with the local paediatric renal team: acute nephritic syndrome, nephrotic syndrome, deranged U&Es, hypertension
Admission should be considered for: children unable to mobilise due to joint pain, children with severe abdominal pain not managed with simple analgesia, those with renal complications
Follow up
Most paediatric units in the UK have robust discharge plans in place for children with HSP to ensure adequate follow up. This usually involves referring to a community nursing team who monitor blood pressure and urine dip every 2 weeks for the first month and then monthly until 6 months
Secondary care follow up should be arranged for those who have persistent proteinuria, frank haematruia, hypertension, or derange renal function and low albumin.
Bibliography
Dalpiaz A, S. R. (2015). Urological Manifestations of Henoch-Schonlein Purpura: A Review. Current Urology, 66-73.
Khader Y, B. C. (2021). Henoch-Schonlein Purpura Presenting as Upper Gastrointestinal Bleed in an Adult Patient. Cureus.
Kim WK, K. C. (2021). Risk Factors for Renal Involvement in Henoch-Schonlein Purpura. Jornal de Pediatria, 646-650.
T, G. (2023, June 20). Henoch-Schonlein Purpura. Retrieved from DermNet: https://dermnetnz.org/topics/henoch-schoenlein-purpura
Wang X, Z. Y. (2016). Henoch-Schonlein Purpura with Joint Involvement: Analysis of 71 Cases. Paediatric Rheumatology, 20.
Written and edited by Dr Rebecca Evans, Paediatric ST3
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