Henoch-Schönlein purpura (HSP) is a systemic vasculitis characterized by purpuric skin lesions unrelated to any underlying coagulopathy, gastrointestinal manifestations, arthritis, and renal involvement. It is the most common type of vasculitis in children and an infrequent condition in adults. The long-term morbidity and mortality of HSP am predominantly attributable to renal involvement. Most studies of renal outcome were done on series of selected patient populations with kidney dysfunction attended in reference centers. There has been a relative paucity of clinical and epidemiologic studies on HSP in children over the past few years. To investigate this syndrome further, we examined the incidence, clinical spectrum, and outcome, and, in particular, the risk factors implicated in the development of permanent renal damage in an unselected population of children diagnosed with HSP at the single reference hospital for a defined population in northwestern Spain over a 20-year period. Seventy-eight children were classified as having HSP. The median age at the onset of symptoms was 5.5 years. Girls outnumbered boys (54%). Cases occurred more commonly in fall and winter. A history of upper respiratory infection before the onset of the vasculitis was not uncommon. The overall average annual incidence rate for the 20-year period (1980-1999) was 10.45/100,000 people aged 14 years and younger. Abdominal pain and/or joint manifestations preceded the onset of purpura in 31% of the children. All children developed nonthrombocytopenic palpable purpura during the course of the disease. Arthritis, generally involving the lower extremities, was seen in 65% of patients. Gastrointestinal bleeding occurred in 31% and renal manifestations in 54% of children within the first 3 months after the onset of symptoms. All but 1 of the patients with renal manifestations had hematuria, associated with proteinuria in 19 of 41 cases. Sixty-nine of the 78 cases were followed for at least 1 year. After a median follow-up of 7 years, 8 (11.6%) of the 69 patients had persistent hematuria with proteinuria; however, none of them had developed renal insufficiency. Hematuria at the onset of disease or renal manifestations within the first 3 months after the onset of symptoms of the vasculitis and relapses were significantly more common in the group of patients with renal sequelae. Of note, the presence of nephrotic syndrome during the course of the disease was generally associated with permanent renal involvement (renal sequelae) (p < 0.001); however, the age at the onset of disease was not associated with a different disease severity and outcome. Using discriminant analysis the best predictor for renal sequelae was the presence of nephrotic syndrome during the first 3 months after the onset of symptoms. The odds ratio for renal sequelae in patients who had developed nephrotic syndrome was 22.9, p < 0.0001. Using this model, 65 of 69 (94.2%) patients with a follow-up of at least 1 year were classified correctly for the risk of developing renal sequelae. In conclusion, in northwestern Spain, HSP is a common, generally benign, and self-limited vasculitis, although some children, in particular those who develop nephrotic syndrome, suffer permanent renal involvement. Long-term follow-up studies in unselected patients from other countries are required for better understanding of the nature and outcome of this syndrome.
