A high white blood cell count usually means one of the following has increased the making of white blood cells:

  1. An infection.
  2. Reaction to a medicine.
  3. A bone marrow disease
  4. An immune system issue.
  5. Sudden stress such as hard exercise.
  6. Smoking.

Specific causes of a high white blood cell count include:

  1. Allergy, especially severe allergic reactions
  2. Asthma
  3. Bacterial, viral, fungal or parasitic infections
  4. Burns
  5. Churg-Strauss syndrome
  6. Medicines, such as corticosteroids and epinephrine
  7. Hay fever (allergic rhinitis)
  8. Leukemia
  9. Lymphoma
  10. Myelofibrosis (a bone marrow disorder)
  11. Polycythemia vera
  12. Pregnancy
  13. Rheumatoid arthritis
  14. Sarcoidosis
  15. Smoking
  16. Tuberculosis
  17. Vasculitis
  18. Whooping cough

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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Dec. 15, 2022