OBJECTIVE
Immune thrombocytopenic purpura (ITP) is an autoimmune bleeding disorder, characterized by isolated thrombocytopenia (platelet count <100.000/µL). Infants less than three-months old with ITP have higher risk of cerebral hemorrhage, so intravenous immunoglobulin (IVIG) is the best choice that can increase platelet count more rapidly than corticosteroids in the first 48 hours of treatment (Farhangi, 2015). The dose of IVIG that can be given is 0,4-1 g/kg/day (1-5 days). Choi (2016) concluded that 1 g/kg/day in 1 or 2 days IVIG treatment showed platelet count recovery in newly diagnosed ITP in children. 
The objective of this case report is to know the laboratory and clinical manifestation changes of a single dose IVIG treatment in newly diagnosed ITP in early infant using the minimum dose (0,4 g/kg).

CASE
A 86-days-old boy came with petechiae and hematomas in his body since two days before hospital admission date. There were no fever and no hemophilia family history. He was exclusively breast fed and thriving well. He had complete immunization according to his age (Hepatitis B, Polio, BCG). Petheciae were found on head, chest, abdomen, all extremities; hematomas on lower extremities. Laboratory findings were platelet count 24.000/µL, hemoglobin 11 g/dL, total leucocyte 8.000/µL, neuthrophil 16, lymphocyte 71, monocyte 12, bleeding time 3 minutes, clotting time 5 minutes. This newly diagnosed ITP was treated with single dose IVIG 0,4 g/kg body weight. Platelet count after 12 and 24 hours of treatment were 74.000/µL and 84.000/µL. Petheciae and hematomas in his body started to fade. There were no adverse reactions of IVIG (headache, palpitation, vomit, fever). 

CONCLUSION
Single IVIG administration with minimum dose (0,4 g/kg) is effective in increasing platelet count and improving clinical manifestations in newly diagnosed ITP in early infant. It is also safe for early infant because the adverse reactions didn’t happen.