Petechiae
Epistaxis
Gingival bleeding
Menorrhagia
GI bleeding
Intracranial hemorrhage
Immune thrombocytopenic purpura
Marrow infiltration 
Thrombotic thrombocytopenic purpura
Viral infections 
Disseminated intravascular coagulation
Marrow suppression 
Heparin-Induced Thrombocytopenia 
Congenital thrombocytopenia