The most common cause of low platelet count (thrombocytopenia) is an underlying health condition or the use of certain medications. Specifically, immune thrombocytopenia purpura (ITP), an autoimmune disorder where the immune system destroys platelets, is one of the most frequent causes

. Other common causes include:

• Bone marrow disorders such as leukemia, aplastic anemia, or myelodysplastic syndrome that reduce platelet production

• Viral infections like hepatitis C and HIV that impair platelet production or increase destruction

• Medications, including chemotherapy, certain antibiotics, and blood thinners, which can suppress bone marrow or trigger immune destruction of platelets

• Enlarged spleen (splenomegaly), often due to liver disease or blood disorders, which traps platelets and lowers circulating platelet count

• Heavy alcohol consumption, which suppresses platelet production and damages the liver, reducing thrombopoietin production needed for platelet formation

In summary, low platelet count is most commonly caused by either decreased production in the bone marrow due to diseases or medications, increased destruction from immune causes like ITP, or sequestration in an enlarged spleen often related to liver disease

. Among these, immune thrombocytopenia purpura (ITP) is a leading specific diagnosis for unexplained low platelets.

Key points:

• Immune thrombocytopenia purpura (ITP) is a common cause of low platelets

• Bone marrow disorders and cancers reduce platelet production

• Viral infections (HIV, hepatitis C) can cause thrombocytopenia

• Medications and chemotherapy are frequent causes

• Enlarged spleen from liver disease or blood disorders traps platelets

• Alcohol abuse affects platelet production and liver function