Chronic immune thrombocytopenia is a disease in which the immune system destroys platelets (blood cells involved in the clotting process). Patients with ITP have abnormal bruising and bleeding, and severe disease can be life threatening. For many patients, standard drug treatments are not effective, and many of the drugs used may have significant side effects with long-term use. Among the articles in this issue, some focus on the traditional and newer treatments for the disease. Other articles focus on diagnosis and treatment of the disease in pregnancy, lymphoproliferative disorders, in thyroid disease, in rheumatologic disorders, and in children. Also discussed are infectious causes.