What is your approach to an infant (<12 mo) with new onset petechiae and thrombocytopenia, with labs consistent with ITP?

In an older (1-6 year old) child with apparent ITP, less work up might be needed. While many tests are possible, in this case, labs consistent with ITP, I would interpret as including a CBC otherwise normal for age without blasts on a smear (if this is not true, the differential is much wider). If i...