Implications of upper respiratory tract infections and drugs in the clinical spectrum of Henoch-Schönlein purpura in children.

OBJECTIVE To assess whether children with Henoch-Schonlein purpura (HSP) who had an upper respiratory tract infection (URTI) or received medication prior to the onset of the disease exhibited a different clinical spectrum of features and outcome from children without such a history. METHODS Retrospective study of children (< or = 14 years old) with HSP diagnosed from 1980 through December 2001 at the single hospital for the Lugo region (Northwest Spain). Children with primary cutaneous vasculitis were classified as having HSP according to currently used criteria. Drugs or URTI were considered precipitating events if any new medication was taken or an URTI had occurred within a week prior to the onset of the vasculitis. A comparative analysis of clinical and laboratory features according to the presence or absence of URTI and drugs was conducted. RESULTS Eighty-six children fulfilled the classification criteria for HSP. Eight of them were excluded from this analysis due to insufficient follow-up (less than 1 year post-diagnosis). An URTI and a history of drugs were reported to occur in 32/78 (41%) and 23/78 (30%) children respectively. No differences in the age at the onset of the disease, gender and seasonal incidence between children with or without URTI were observed. However, 23/32 (72%) children with URTI had hematuria with or without proteinuria, compared with only 18/46 (39%) children without history of URTI (p = 0.004). This higher incidence of renal manifestations in HSP with URTI was not associated with more severe nephritis or with a significantly higher frequency of renal sequelae or relapses of the disease. No statistically significant differences between children with or without a history of drugs were observed. CONCLUSION Although in unselected children with HSP a history of URTI seems to be associated with a higher incidence of nephritis, it does not influence the outcome of the disease.