Dexamethasone or any steroids suppresses inflammatory mediators....it suppresses the immunity too....and causes steroid related leucocytosis..... despite of no infection....

White blood cells(WBC) are of different types viz neutrophils, Lymphocytes, monocytes etc. Corticosteroids ( like dexamethasone) has a differential effect on these cells. When Dexa cause an increase in neutrophils, it has an opposite effect on lymphocytes. And this increase and decrease are not actual in numbers but its a redistribution of these cells to other places. For eg in Bronchial asthma, neutrophils from blood comes out and acts on alveoli of lungs causing inflammation and scarring, when we give steroids these cells redistributes back to blood stream and decreases inflammation. Thats why we give steroids in bronchial asthma.

Dexamethasone or any steroid when administered actually suppresses inflammatory mediators.