Immune thrombocytopenic purpura (ITP) in children may present either as an acute, self-limited, immune mediated condition or as a chronic autoimmune disorder. Ten to 20% of children develop chronic ITP with similar clinical features to those seen in adults. In acute ITP a cross-reactive immune response directed against an infectious agent has been proposed, while chronic ITP may be perpetuated by a constant HLA-DR - stimulated immune response with enhanced cylokine production, increased activation of T-cells and increased production of specific autoantibodies.

Treatment of ITP is indicated in children at risk or with overt signs of bleeding. Treatment is necessary for a child with mucosal bleeding and platelet counts below 20×109/L. The therapy of ITP focuses on measures modulating the immune response and includes intravenous immunoglobulins and anti Rh (D) immunoglobulin. Immuno-suppressive treatment with corticosteroids or cytostatic agents are used as an alternative treatment strategy.

Acute bleeding in children with ITP may warrant rapid increase in platelets. As a follow up of earlier studies, two Canadian multicenter studies have analysed prospectively children diagnosed with acute ITP and platelet counts below 20×109/L. A single dose of 0.8 g IVIg/kg body weight was sufficient and comparable to the more traditional larger dose of total 2 g/kg body weight given within 48 hours. Importantly, treatment with the lower IVIg dose decreases the duration and the cost of hospitalization. Treatment with corticosteroids was recommended as the second choice. Longterm corticosteroid treatment in children should be avoided due to unacceptable side effects. Treatment with high-dose methylprednisolone or dexamethasone administered either intravenously or orally remains controversial due to efficacy and side effects. Based on these findings the recently published guidelines of the American Society of Hematology panel recommend the use of IVIg in preference to corticosteroids for the treatment of children with ITP.

Longterm effects of treatment in ITP must be interpreted with caution, since the natural history of ITP in children is one of gradual spontaneous resolution. Several uncontrolled studies reported that patients with chronic ITP displayed longlasting recovery when treated with repeated courses of IVIg, or with high dose cyclic dexamethasone treatment. A prospective randomized multicenter study in children with early chronic ITP has recently been initiated. The study objectives are to determine the influence of cyclic treatment (i.e. high dose oral dexamethasone of IVIg) against conventional treatment or observation alone in children with early chronic ITP (6-9 months duration, stage 3 ITP). Such studies will provide evidence as to the natural history of ITP and the appropriate treatment regiments for children who develop chronic ITP.