Prednisone or Dexamethasone in Newly Diagnosed, Previously Untreated Primary Immune Thrombocytopenic Purpura

RATIONALE: Drugs, such as prednisone and dexamethasone, may change the immune system and be an effective treatment for primary immune thrombocytopenic purpura. It is not yet known which drug is more effective in treating primary immune thrombocytopenic purpura. PURPOSE: This randomized phase III trial is studying high-dose dexamethasone to see how well it works compared to standard-dose prednisone in treating patients with newly diagnosed, previously untreated primary immune thrombocytopenic purpura.