Which of the following is due to Delayed Hypersensitivity (Type IV) type of reaction?

AIIMS Bhopal NO - 2018 (Shift-1st)

Medical & Surgical Nursing

Easy

Appeared in: AIIMS Bhopal NO - 2018 (Shift-1st)

Explanation

Contact dermatitis is a classic example of a Type IV hypersensitivity reaction, also known as delayed-type hypersensitivity (DTH).
This reaction is mediated by T-lymphocytes (T-cells), specifically CD4+ T-helper cells and/or CD8+ cytotoxic T-cells, not by antibodies.
The clinical manifestations, such as redness, itching, and blistering, typically appear 24 to 48 hours after the skin comes into contact with an allergen (e.g., poison ivy, nickel, latex).
The delay is due to the time it takes for T-cells to be recruited to the site of antigen exposure, become activated, and release cytokines that cause inflammation and tissue damage.

Option A: Anaphylaxis is a systemic and severe Type I (immediate) hypersensitivity reaction.
Option B: Serum sickness is a Type III (immune complex-mediated) hypersensitivity reaction.
Option D: Atopy describes a genetic tendency to develop allergic diseases, which are primarily Type I (IgE-mediated) hypersensitivity reactions.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Hypersensitivity Reactions as background academic context rather than a clinical decision trigger.
Nurses must be able to distinguish between different hypersensitivity reactions to provide appropriate and timely care. A delayed reaction like contact dermatitis requires different management (e.g., topical corticosteroids, allergen avoidance) than an immediate reaction like anaphylaxis (e.g., epinephrine, airway management).
Patient education is a key nursing role. For contact dermatitis, nurses teach patients to identify and avoid specific triggers (e.g., nickel in jewelry, latex in gloves) and how to manage skin symptoms.
Patch testing is a diagnostic tool used to identify the specific allergens causing Type IV contact dermatitis. Nurses may be involved in applying patches and interpreting the delayed skin reactions.

How to Approach the Question

First, identify the core concept in the question stem: 'Delayed Hypersensitivity (Type IV)'.
Recall the key features of Type IV reactions: they are cell-mediated (T-cells), not antibody-mediated, and have a delayed onset (24-48 hours).
Systematically evaluate each option against these criteria.
Anaphylaxis is a rapid, immediate reaction, so it's not Type IV.
Serum sickness is caused by immune complexes, which points to Type III.
Contact dermatitis is a skin reaction that develops over 1-2 days after exposure, fitting the description of a delayed, cell-mediated response.

Concept Tested & Keywords

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E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 81-83

E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) pp. 163-165, 159-161