Which WBC Increases in Allergy?
During an allergic reaction, the eosinophil and basophil white blood cell counts increase. While various sources cite either eosinophils or basophils as the primary WBC increasing during an allergic response, both play significant roles.
Eosinophils are a type of white blood cell that's crucial in combating parasitic infections and modulating allergic responses. Elevated eosinophil counts (eosinophilia) are often observed in individuals experiencing allergic reactions. 1 This increase is a result of the immune system's response to allergens. The higher number of eosinophils helps to fight off the perceived threat, though this response can also contribute to allergy symptoms. 2 For example, in eosinophilic gastritis, an increase in eosinophils is linked to allergens, infections, medications, or even cancer. 3
Basophils and Allergies
Basophils, another type of white blood cell, also play a key role in allergic reactions. They release histamine and other inflammatory mediators upon encountering allergens, contributing to the characteristic symptoms of allergy, such as inflammation and swelling. 4 Although making up less than 1% of all leukocytes, their presence and activation during an allergic response are critical. Their increased presence is a direct response to allergen exposure. 5 Allergic responses, including asthma attacks, are associated with high white blood cell counts, and basophils are directly involved in the inflammatory cascade. 6 The release of histamine by basophils is a hallmark of allergic reactions.
Other Factors Affecting WBC Count
It is important to note that a high white blood cell count (leukocytosis) can result from various conditions beyond allergies, including infections (bacterial, viral, fungal), certain cancers (leukemia, Hodgkin's disease), and tissue damage. 7 Smoking can also influence white blood cell counts, particularly eosinophils. 8
Therefore, while both eosinophils and basophils increase in allergy, interpreting a high WBC count requires considering the overall clinical picture.
