Normal platelet count is 150,000 to 450, 000 cells per microlitre

Thrombocytopenia is < 150,000 cells/ microliter

Causes 

Reduced production

• Congenital
• Thrombocytopenia and absent radius syndrome
• Fanconi anaemia
• Wiskott Aldrich syndrome
• Aplastic anaemia

Decreased platelet survival

• Immune-mediated thrombocytopenic purpura
• Neonatal isoimmune thrombocytopenia
• Alloimmune neonatal thrombocytopenia
• Neonatal ITP
• Infections
• Drug-induced thrombocytopenia
• Autoimmune conditions
• Malignancy
• Non-immune-mediated conditions
• Disseminated intravascular coagulation
• Hemolytic uremic syndrome
• Thrombotic thrombocytopenic purpura
• Cyanotic congenital heart disease
• Lung diseases
• Drug-induced