Can corticosteroids increase White Blood Cell (WBC) count?

From the Guidelines

Yes, steroids can raise white blood cell (WBC) counts, as they cause an increase in total WBC count, particularly neutrophils, within hours of administration 1. This effect occurs through multiple mechanisms: steroids reduce the adhesion of neutrophils to blood vessel walls (demargination), increase the release of neutrophils from bone marrow, and extend neutrophil survival by inhibiting apoptosis.

Key Points

• The WBC elevation is typically dose-dependent and can be significant, sometimes reaching 15,000-30,000 cells/μL or higher.
• This steroid-induced leukocytosis is a normal physiological response rather than a sign of infection.
• The effect is temporary and reversible, with WBC counts typically returning to baseline after the steroid is discontinued.
• The use of steroids, such as prednisone, is a common treatment approach in various medical conditions, including immune thrombocytopenia (ITP) 1, and their impact on WBC counts should be considered in clinical practice.

Clinical Implications

• An elevated WBC count in a patient taking steroids may not necessarily indicate infection or inflammation, potentially avoiding unnecessary diagnostic testing or antibiotic treatment.
• It is essential to recognize this phenomenon in clinical practice to provide appropriate patient care and management.
• The dosage of prednisone, for example, can range from 0.5 to 2 mg/kg per day, and its administration should be carefully monitored to minimize potential complications 1.

From the Research

Steroids and WBC Count

• Steroids, specifically corticosteroids, can cause an increase in white blood cell (WBC) count, a condition known as leukocytosis 2, 3, 4.
• The degree of leukocytosis is related to the dosage of corticosteroids administered, with higher doses resulting in greater increases in WBC count 2, 3.
• The increase in WBC count is predominantly due to an increase in polymorphonuclear white blood cells, with a concurrent decrease in lymphocytes and eosinophils 3, 4.
• The mechanism of corticosteroid-induced leukocytosis is thought to involve the decreased expression of neutrophil adhesion molecules, such as Mac-1 and L-selectin, leading to increased release of neutrophils from the bone marrow and decreased adhesion to the endothelial surface 4.

Clinical Implications

• Clinicians should be aware of the potential for corticosteroids to increase WBC count, as this can complicate the diagnosis of infection 2, 3, 5.
• In patients receiving corticosteroids, an increase in WBC count should be interpreted with caution, as it may not necessarily indicate infection 2, 3, 5.
• The effects of corticosteroids on WBC count can vary depending on the specific context, such as in patients with COVID-19, where leukopenia may be associated with a better response to systemic corticosteroid therapy 6.

Mechanisms of Action

• Corticosteroids exert their effects on WBC count through both genomic and non-genomic mechanisms, mediated by glucocorticoid receptors 5.
• The genomic mechanisms involve the regulation of gene expression, leading to changes in the proliferation, differentiation, and apoptosis of white blood cells 5.
• The non-genomic mechanisms involve the rapid activation of signaling pathways, leading to changes in the activation and secretion of white blood cells 5.