Definitions
systemic vasculitis(small blood vessels) affecting the skin, known also as anaphylactoid purpura
Pathophysiology
IgA deposition in vessel walls initiates an inflammatory cascade leading to vessel necrosis
Elevated IgA anticardiolipin antibodies and TGF-beta occur
Multiple organ involvement- disease of skin, kidneys, GI tract & joints
Aetiology
unknown(autoimmune)
infectious causes have been implicated: Beta-hemolytic, Streptococcus
genetic component- familial
Epidemiology
incidence 20 per 100,000, 3-5 years old
M:F=2:1
primarily in the fall, winter, spring
Presentation
Characteristic skin rash
- first feature in 50%, cornerstone of dx
- symmetrically distributed over the bittocks, extensor surfaces of the arms, legs, ankles.
- Trunk is spared, unless trauma
- initially urticarial, then maculopapular & purpuric
- palpable & may recur over several weeks
Athralgia
- ⅔ of pts
- knee & ankle
- usually resolves before the rash goes
Periarticular oedema
Colicky abdominal pain
- can be treated with steroid
- Gastrointestinal petechiae can cause haematemesis & melaena
- Intussusception can occur & can be particularly difficult to diagnose
- rare complications: ileus, protein-losing enteropathy, orchitis, CNS involvement
- painful tender testicle/scrotum
Glomerulonephritis
- 80% have haematuria or mild proteinuria
- usually complete recovery
- nephrotic syndrome if severe
Investigation
- no confirmatory test/diagnostic lab, clinical dx
- Lab findings: leukocytosis with left shift, anaemia, elevated IgA (50-70%), elevated ESR, prolong PT
- Kidney biopsy if nephrotic syndrome
- upper GI series with small bowel follow through- thickened folds, pseudotumours, hypomotility, thumbprinting
- Doppler differentiate HSP from testicular torsion
Management
Outpatient
Supportive- fluid, pain control - NSAIDs (CI in glomerulonephritis)
monitor electrolytes, BUN/Creatinine, BP
In severe disease- monitor vitals, hamatocrit, stool guaiac testing, CT if mental status change
Prognosis & Complications
self-limited
persist for a month, shorter in younger pts
Recurs in 40%
Morbidity associated with renal, may become chronic, ESRF in 2-5%
Long-term mortality <1%
systemic vasculitis(small blood vessels) affecting the skin, known also as anaphylactoid purpura
Pathophysiology
IgA deposition in vessel walls initiates an inflammatory cascade leading to vessel necrosis
Elevated IgA anticardiolipin antibodies and TGF-beta occur
Multiple organ involvement- disease of skin, kidneys, GI tract & joints
Aetiology
unknown(autoimmune)
infectious causes have been implicated: Beta-hemolytic, Streptococcus
genetic component- familial
Epidemiology
incidence 20 per 100,000, 3-5 years old
M:F=2:1
primarily in the fall, winter, spring
Presentation
Characteristic skin rash
- first feature in 50%, cornerstone of dx
- symmetrically distributed over the bittocks, extensor surfaces of the arms, legs, ankles.
- Trunk is spared, unless trauma
- initially urticarial, then maculopapular & purpuric
- palpable & may recur over several weeks
Athralgia
- ⅔ of pts
- knee & ankle
- usually resolves before the rash goes
Periarticular oedema
Colicky abdominal pain
- can be treated with steroid
- Gastrointestinal petechiae can cause haematemesis & melaena
- Intussusception can occur & can be particularly difficult to diagnose
- rare complications: ileus, protein-losing enteropathy, orchitis, CNS involvement
- painful tender testicle/scrotum
Glomerulonephritis
- 80% have haematuria or mild proteinuria
- usually complete recovery
- nephrotic syndrome if severe
Investigation
- no confirmatory test/diagnostic lab, clinical dx
- Lab findings: leukocytosis with left shift, anaemia, elevated IgA (50-70%), elevated ESR, prolong PT
- Kidney biopsy if nephrotic syndrome
- upper GI series with small bowel follow through- thickened folds, pseudotumours, hypomotility, thumbprinting
- Doppler differentiate HSP from testicular torsion
Management
Outpatient
Supportive- fluid, pain control - NSAIDs (CI in glomerulonephritis)
monitor electrolytes, BUN/Creatinine, BP
In severe disease- monitor vitals, hamatocrit, stool guaiac testing, CT if mental status change
Prognosis & Complications
self-limited
persist for a month, shorter in younger pts
Recurs in 40%
Morbidity associated with renal, may become chronic, ESRF in 2-5%
Long-term mortality <1%
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