What Causes a Temporary Increase in a Platelet Count?

In reactive thrombocytosis, the platelet count is elevated due to another disorder, such as an infection, bleeding, iron deficiency, cancer, destruction of red blood cells, removal of the spleen, inflammatory disease or other blood condition, the Merck Manual states. If the primary problem is treated successfully, the platelet count returns to normal.

Platelets help blood clot, according to the Seattle Cancer Care Alliance. There are normally 150,000 to 450,000 platelets per microliter of blood. However, when the count climbs toward 1 million, the patient usually has reactive, or secondary, thrombocytosis.

Patients with reactive thrombocytosis typically have no symptoms, not even abnormal clotting, the Cleveland Clinic explains. If this is the case, doctors offer no specific treatment. Efforts are made to resolve the condition that led to the elevated platelet count.

Reactive thrombocytosis is often discovered during ordinary medical procedures, reveals Mayo Clinic. For instance, a doctor sees evidence of an infection during a routine physical, or a standard blood test uncovers an elevated platelet count. In addition, thrombocytosis sometimes is found when the primary condition is being explored and treated, the Cleveland Clinic notes.

In contrast, abnormal bone marrow cells manufacture excessive numbers of platelets in essential or primary thrombocytosis, the Cleveland Clinic describes. Platelet counts run from 500,000 to over 1 million, reveals the Seattle Cancer Care Alliance. Most people with essential thrombocytosis display no symptoms and need no treatment, Cleveland Clinic acknowledges. Those that do often take low doses of aspirin to prevent blood clots.