Henoch-Schönlein purpura (HSP) is a common, benign vasculitis in childhood which occasionally follows a protracted course and prolonged length of hospital stay. We aimed to determine clinical and laboratory characteristics that allow prediction of prolonged length of hospital stay (4 or more days) in HSP patients. We have retrospectively reviewed all HSP cases that were admitted to the Dana Duek Children's hospital between 2000 and 2013. Univariable analysis was performed to study the variables that were statistically related to length of hospital stay. These variables along with other clinically relevant variables were analyzed using stepwise backward multiple regression analysis. Variables that remained significant in the final analysis were correlated with length of stay, were each given specific weight (according to their contribution to the final R(2)) and were used to assemble an HSP presentation severity score. Out of 107 charts that were screened, 89 children were retrieved for analysis. In univariate analysis, variables that were associated with prolonged (>4 days) length of stay were: abdominal pain as initial sole presentation, C-reactive protein (CRP) 45 mg/dL (1 or 0 point) and patient's age > 6 years (0.5 or 0 points). A score of ≥3 in patients diagnosed with HSP predicted a prolonged length of stay with a positive predictive value of 93 %. The HSP presentation severity score index that we describe here may serve as a practical tool to assess severity of HSP which may eventually reflected as prolonged length of hospital stay. This score should be validated in the future in an ongoing prospective study.