Primary (no other evident associated disease)

• Hereditary neutrophilia
• Chronic idiopathic neutrophilia
• Chronic myelogenous leukemia (CML) and other myeloproliferative diseases
• Familial myeloproliferative disease
• Congenital anomalies and leukemoid reaction
• Leukocyte adhesion deficiency (LAD)
• Familial cold urticaria and leukocytosis

Secondary

• Infection
• Stress neutrophilia
• Chronic inflammation
• Drug induced: Steroids, lithium, tetracycline, G-CSF.
• Nonhematologic malignancy
• Generalized marrow stimulation as in hemolysis
• Asplenia and hyposplenism

References:

1. Kyono W, Coates TD. A practical approach to neutrophil disorders. Pediatr Clin North Am. 2002 Oct;49(5):929-71, viii. [Medline]