The study group comprised of 19 children and adolescents that were diagnosed with HSP. Endothelial function was compared to that of a known control group of 23 healthy children and adolescents matched controls. Among the control group, there was no differences in RHI values between male and female (1.85 ± 0.35 vs 1.8 ± 0.3 respectively p = 0.2) as well as between age and RHI levels in the control group (R-0.29 P = 0.18).