find why and treat. You should have some work up to find out why you you have iron deficiency anemia. Then, you also would need to get treatment as indicated. There are many reasons why iron deficiency can occur- bleeding, decrease iron absorption etc. Thrombocythemia can be related to the iron deficiency anemia. When iron deficiency is resolved usually platelet will normalize. If not, further investigation is neede.
Replace iron. Thrombocythemia (thrombocytosis) or elevated platelet count is frequently associated with iron-deficiency anemia. Correction of the anemia by iron replacement will frequently correct the high platelet count back to normal. If after complete replacement of iron deficiency, the platelet count remains elevated, then a full work-up for other causes of the thrombocythemia should be done.