Pulse high dose dexamethasone (Arm 1)

1. Patients will receive 40 mg of oral dexamethasone daily for four consecutive days.
2. Other treatments should be considered if there was a platelet count of 30X109/L or less by day 14
3. If the patient had a platelet count of more than 30X109/L after four days of dexamethasone treatment, no further treatment will be given.
4. If the platelet count drops below 30X109/L within the first 6 months, another four-day course of dexamethasone will be given, followed by 15 mg of prednisone daily, with gradual tapering.
5. Patients whose platelet counts can not be maintained at 30X109/L will be offered other treatments.

Conventional dose prednisone (Arm 2)

1. Prednisone, 1 mg/kg is started at diagnosis. If the platelet count is more than 100X109/L, the dose should be used for 4 weeks minimally and then tapered by 10 mg/1 wk until the dose reaches 0.5 mg/kg of body weight and by 5 mg/1 wk thereafter. (Ann Intern Med 1997, 126, 307-14). If the platelet count is between 30X109/L and 100X109/L, prednisone 1 mg/kg should be used for 8 weeks maximally and then tapered by 10 mg/2 wk until the dose reaches 0.5 mg/kg of body weight and by 5 mg/2 wk thereafter.
2. Guideline of prednisone tapering Duration of prednisone treatment: 3-6 months

Endpoint definitions and criteria for evaluation: This study is designed to compare the effectiveness of high dose dexamethasone with conventional dose prednisone for patient with ITP. The effectiveness will be evaluated in terms of response rate and platelet count at 6 months after the treatment