Introduction: Primary immune thrombocytopenia (ITP) is a bleeding disorder characterized by autoimmune destruction and impaired production of platelets. Immunosuppressive drugs are the main treatment and may increase risk of infection.Areas covered: This systematic review included studies incorporating adult patients with primary ITP and infectious outcomes. Studies comparing risk of infection with the general population were included as primary and studies without this comparison were considered secondary. Three primary and ten secondary studies were included. The main findings: 1-year adjusted relativerisk of infection was 4.5 (95% CI, 3.3 -6.1) fold elevated compared to the general population. When comparing splenectomized with non-splenectomized ITP patients, the +1-year adjusted relative-risk of infection was 4.0 (95% CI, 2.8 -5.6). The unadjusted 5-year mortality rate-ratio for infectionrelated deaths was 6.0 (95% CI, 3.0 -11.8) in one study, and the hazard ratio was 2.4 (95% CI, 1.0 -5.7) for fatal infections in another.Expert opinion: This review emphasizes that patients with ITP have increased risk of infection.Since ITP is a benign hematologic disease, it is important to assess the extent and causes of infection in the clinical care and considerations before initiating treatment. More homogeneous studies are needed on this topic.