Which type of white blood cell is most commonly elevated during allergic reactions?

Eosinophils are a specific type of white blood cell that play a crucial role in the body's immune response, particularly during allergic reactions and parasitic infections. When the body encounters an allergen, eosinophils are often mobilized from the bone marrow and circulating blood into tissues where they can exert their effects. They are involved in the response to allergens through the release of various substances, including inflammatory mediators and enzymes, which contribute to the symptoms associated with allergies such as asthma, hay fever, and other atopic conditions. Their elevated levels during allergic reactions are a key marker used by healthcare providers to assess allergic diseases.

Other types of white blood cells, such as monocytes, lymphocytes, and neutrophils, have distinct functions in the immune response but are not specifically elevated during allergic reactions in the same way that eosinophils are. Monocytes generally differentiate into macrophages and play roles in chronic inflammation and phagocytosis. Lymphocytes are more associated with viral infections and specific immune responses. Neutrophils typically respond to bacterial infections and are not primarily involved in allergic processes.