Stressful life events and anxiety usually cause an increase in platelet volume and activity through various mechanisms.

What is the most common cause of high platelet count?

Infection. In both children and adults, infections are the most common cause of an elevated platelet count. 1 This elevation can be extreme, with platelet counts greater than 1 million cells per microliter.

Can platelets be high for no reason?

Abnormally high platelet production may occur independently, for reasons that are not known (primary thrombocythemia), or as a symptom of another condition (secondary thrombocytosis).