Which one of the following occurs in allergy?

Appeared in: BHU NO-2019

Explanation

Eosinophilia is defined as an increased number of eosinophils, a specific type of white blood cell, in the blood.
It is a hallmark feature of allergic diseases, including asthma, allergic rhinitis (hay fever), and atopic dermatitis (eczema).
During an allergic reaction, the body releases specific chemical signals called eotaxins, which actively recruit eosinophils to the site of inflammation.
Once at the site, eosinophils release proteins from their granules that contribute to the inflammation and tissue damage seen in chronic allergic conditions.

Option B: This is an increase in monocytes, which is not a primary feature of acute allergic reactions.
Option C: This is an increase in neutrophils, the body's main defense against bacteria, not allergens.
Option D: This is an increase in lymphocytes, which primarily fight viral infections.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular response in allergic reactions as background academic context rather than a clinical decision trigger.
Understanding the different types of leukocytosis (high WBC count) is crucial for nurses when interpreting a Complete Blood Count (CBC) with differential, as it helps narrow down the potential cause of a patient's illness.
A finding of eosinophilia on a lab report should prompt the nurse to assess the patient for signs and symptoms of allergies (e.g., rash, wheezing, rhinitis) or ask about recent travel history, which could suggest a parasitic infection.
What if? If a patient has a high total WBC count with a 'left shift' (increased immature neutrophils), the priority concern shifts from allergy to a severe bacterial infection, requiring urgent medical attention and antibiotic therapy.

How to Approach the Question

First, identify the core concept of the question, which is the specific cellular response associated with 'allergy'.
Recall the primary functions of the different types of white blood cells listed in the options.
Evaluate each option: Neutrophils are primarily for bacteria, lymphocytes for viruses, and monocytes for chronic inflammation and phagocytosis.
Recognize that eosinophils have a specialized role in modulating inflammatory responses, particularly those triggered by allergens and parasites.
Select the option that directly matches the pathophysiology of an allergic reaction.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 pp. 1305-1307, 1325-1327

E6 Physiology Ganong 27e Vol 1 Part 1 p. 97-99

Practise the full BHU NO-2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.