16. Neutrophilia
Neutrophilia can be related to myeloproliferative disorders but more commonly results from infection or inflammation. Drugs can also induce leukocytosis. Glucocorticoids cause neutrophilia by inducing the release of neutrophils from the bone marrow [78]. Although variable, glucocorticoids typically do not cause leukocytosis over 20 000/uL or a left shift. Such an elevation in WBC counts, or an increase in bands, might suggest the presence of infection [79]. Adrenergic-agonists and epinephrine produce neutrophilia by releasing neutrophils from the marginated pool [78]. Lithium causes mild neutrophilia and was used as treatment for neutropenia prior to the availability of CSFs [80].
Leukocytosis is commonly seen with G/GM-CSF, frequently given to reduce the severity and duration of neutropenia from chemotherapy. Sweet's Syndrome (acute febrile neutrophilic dermatosis), characterized by tender erythematous skin lesions, fever, and neutrophilia, can be induced by drugs such as trimethoprim-sulfamethoxazole, other antibiotics, and granulocyte colony stimulating factor, amongst others [81]. The syndrome can also be idiopathic or paraneoplastic.