Data from this registry will be used to generate descriptive statistics on demographics, clinical characteristics including prevalence and incidence of co-morbidities, treatment patterns, and adverse outcomes (resulting from treatment or disease) on ITP patients on an annual basis. The information will be generated at the national or combined-country level. Furthermore, each institution will have an access to its data and may choose to generate descriptive statistics for its specific institution on a more frequent, ad-hoc basis. New research questions or questions addressing a subset of registry patients to take advantage of combined registry data will require a separate protocol and review by independent committees