Treatment is directed at the prevention of haemorrhagic shock. Standard dose prednisolone does not increase the platelet count. High-dose methylprednisolone therapy in children with Onyalai has been shown to improve platelet count and reduce the requirement for transfusions. Vincristine sulphate may be of benefit to some patients. Splenectomy is indicated in patients with severe uncontrollable haemorrhage. High-dose intravenous gammaglobulin may help in increasing the platelet count and cessation of haemorrhage.

Initial treatment usually consists of the administration of corticosteroids, a group of medications that suppress the immune system. The dose and mode of administration is determined by platelet count and whether there is active bleeding: in urgent situations, infusions of dexamethasone or methylprednisolone may be used, while oral prednisone or prednisolone may suffice in less severe cases. Once the platelet count has improved, the dose of steroid is gradually reduced while the possibility of relapse is monitored. 60–90 percent will experience a relapse during dose reduction or cessation. Long-term steroids are avoided if possible because of potential side-effects that include osteoporosis, diabetes and cataracts.

There is increasing use of immunosuppressants such as mycophenolate mofetil and azathioprine because of their effectiveness. In chronic refractory cases, where immune pathogenesis has been confirmed, the off-label use of the "vinca" alkaloid and chemotherapy agent vincristine may be attempted. However, vincristine has significant side effects and its use in treating ITP must be approached with caution, especially in children.

Inadequate nutrition or the consumption of tainted food are suspected. Both IgG and IgM autoantibodies to platelet and to glycoprotein IIb/IIIa is found in majority of patients.