Can stress, anxiety and allergies cause leukocytosis?

Leukocytosis: Relative leukocytosis can be produced by any condition that causes increased levels of catecholamines like epinephrine, because this causes release of the WBCs from where they are adherent to the walls of the blood vessels. It is not a true increase, but change in disposition. Allergies do have the potential to actually produce an increase in WBCs, often eosinophils.