P>This study assessed the incidence of immune thrombocytopenia (ITP) and characteristics associated with ITP in the paediatric population using the General Practice Research Database (GPRD). Two hundred and fifty-seven paediatric ITP patients were identified out of 1145 incident patients with ITP recorded between 1990 and 2005. The age-specific incidence for ITP in paediatric patients was 4 center dot 2 per 100 000 person-years (PY) [95% confidence interval (CI): 3 center dot 7-4 center dot 8 per 100 000 PY], with a statistically significantly higher incidence in boys compared to girls aged 2-5 years [9 center dot 7 (95% CI: 7 center dot 5-12 center dot 2) per 100 000 PY vs. 4 center dot 7 (95% CI: 3 center dot 2-6 center dot 6) per 100 000 PY, respectively]. By contrast, among teenagers aged 13-17 years, the overall incidence was lower [2 center dot 4 (95% CI: 1 center dot 7-3 center dot 3) per 100 000 PY] with a similar incidence in girls and boys. There was a relationship between age and sex with ITP incidence, suggesting that patterns of disease burden differ among children and teenagers. Evidence of an infection or immunization shortly before ITP diagnosis was apparent in 52 (20 center dot 2%) and 22 (8 center dot 6%) of the 257 paediatric ITP patients, respectively. Two deaths were observed during the study period. ITP is an important although rarely fatal disease in paediatric patients and its aetiology remains unexplained in the majority of cases.