IgA vasculitis

IgA vasculitis (formally known as Henoch-Schonlein purpura (HSP)) is a type of non-thrombocytopaenic immune-mediated small vessel acute leukocytoclastic vasculitis.

It tends to occur in the paediatric population (peak incidence 3-10 years) 3.

In order to differentiate from other types of vasculitides, the four commonly adopted diagnostic criteria by the American College of Rheumatology are:

  • age of onset less than 20 years (although some case series show disease involvement in older individuals)
  • palpable skin purpura
  • gastrointestinal bleeding
  • Intussusception typically ileoileal
  • biopsy showing  granulocytes around small arteriolar/venular walls.

There is deposition of IgA immune complexes in small vessels.

Distribution

Commonest organ systems which get involved are:

  • skin: 95-100%, usually the first organ to get involved
  • gastrointestinal tract: 50-75%
  • joints: ~80% 6
  • kidneys

Rare sites:

  • central nervous system 5,7
Gastrointestinal tract
Plain radiograph

May show evidence of bowel wall thickening due to haemorrhage and/or evidence of bowel obstruction. plain film features are however non-specific.

Fluoroscopy: small bowel follow through

May show evidence of separation of bowel loops, "thumbprinting" and/or mucosal thickening.

CT

May show multifocal bowel thickening, lymphadenopathy, mesenteric oedema and vascular engorgement. Although non-specific, CT findings may aid in the diagnosis of HSP in a young patient with acute gastrointestinal illness along with other, e.g. cutaneous features of HSP. Intussusception typically ileoileal can also be identified.

Ultrasound  

Echogenic kidneys, target or doughnut sign in case of intussusception. HSP has also been shown to cause massive scrotal oedema, and can be a source of severe pain in young boys 9.

The disease often tends to be self-limiting in most instances.

Gastrointestinal tract
Renal

It is named after Eduard Heinrich Henoch, German paediatrician (1820-1910) 8 and Johann Lukas Schönlein, German physician (1793-1864).

On a CT/contrast study for the bowel consider:

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Article information

rID: 7994
Tag: cases
Synonyms or Alternate Spellings:
  • Henoch-Schonlein syndrome
  • Henoch-Schonlein purpura (HSP)
  • HSP
  • Henoch-Schonlein purpura
  • IgAV

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