Some causes of reactive thrombocytosis include Chronic inflammatory disorders (eg, rheumatoid arthritis, inflammatory bowel disease, tuberculosis, sarcoidosis, granulomatosis with polyangiitis) Acute infection Hemorrhage Iron deficiency Hemolysis Cancer Splenectomy or hyposplenism There are also congenital familial thrombocytoses such as those due to thrombopoietin and thrombopoietin receptor gene mutations.