A question: what causes a high platelet count along with a high white blood cell count at the same time?

Reactive or ?: The CBC (complete blood count) consists of many lab numbers, but 3 important ones are the hemoglobin (hgb, a measure of red cells), white blood cell count (WBC) and platelet (plt) count. Wbc and plts may both increase as a result of a reaction such as infection (eg pneumonia), inflammation (arthritis), etc. If prolonged and/or very high it may indicate a bone marrow problem.

Several things: Elevated white count along with elevated white cells can occur with infection or with various blood or bone marrow disorders including benign and malignant conditions. For specific advice consult a physician typically a hematologist