Henoch-Schonlein Purpura: Finding Renal Involvement

IgM in lesional skin of adults with Henoch-Schönlein purpura is an indication of renal involvement.

Takeuchi S, Soma Y, Kawakami T.

J Am Acad Dermatol. 2010 Dec;63(6):1026-9.

Henoch-Schönlein purpura (HSP) is a vasulitis which is generally self limiting especially in children except when systemic involvement, especially renal, is present. This article shows that IgM deposits on the palpable purpura could imply renal involvement.

• HSP is a small-vessel vasculitis which usually affects children but which can occur at any age. It is characterized by palpable purpura which can accompany itself with abdominal pain and renal nephritis (clinically hematuria and proteinuria). The condition is often spontaneously favorable except when the kidney is involved, where in 27% (10 patients out of 37 patients, Shreshta S. et al) advanced kidney disease develops.

• In this retrospective study immunoglobin deposits in direct immunofluorescence (DIF) were examined in 25 patients with HSP. Out of these, 15 showed positive IgM, Of the 12 patients who had renal involvement, 10 patients had positive deposits of IgM. C3 deposits were nonspecific, being present in 22 out of 25 patients. The presence of renal involvement and positive renal findings correlated negatively with that of gastrointestinal involvement.

• Some limitations to the study: Renal involvement was diagnosed clinically when there was presence of hematuria/proteinuria. There is no mention of urinary sediments showing the presence of casts that were specific to renal damage, nor biopsies to show nephritis. The extent of investigations done to exclude other causes of leukocytoclastic vasculitis was not elaborated.

• The findings from this study imply that IgM deposits on lesions of HSP may be predictive of renal involvement  We await further prospective studies with larger patient numbers to see if the findings of this study is reproducible