After giving BCG vaccination, scar gets formed in?

PGIMS Rohtak NO - 2017

Child Health Nursing (Pediatrics)

Easy

Appeared in: PGIMS Rohtak NO - 2017

Explanation

The local reaction to the Bacille Calmette-Guérin (BCG) vaccine follows a predictable sequence of events over several weeks.
A papule first appears at the injection site around 2 to 3 weeks post-vaccination.
This papule progresses to a pustule and then a shallow ulcer, which is most prominent around 4 to 6 weeks.
The healing process concludes with the formation of a permanent, small, round scar between 6 and 12 weeks (approximately 2 to 3 months).
Among the given choices, 2 months is the most accurate timeframe for complete scar formation.

Option A: At 3 days, the initial wheal from the intradermal injection has typically disappeared, and the specific immune reaction leading to a papule has not yet started.
Option B: At 2 weeks, the characteristic red papule is just beginning to form. This is an early inflammatory stage, not the final healed scar.
Option C: At 1 month (around 4 weeks), the lesion is usually at its most active phase, presenting as a pustule or a shallow ulcer covered by a crust. The healing process is not yet complete.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Timeline of local reaction and scar formation after BCG vaccination as background academic context rather than a clinical decision trigger.
Nurses play a crucial role in educating parents about the normal progression of the BCG site reaction. This knowledge helps prevent anxiety and inappropriate interventions like applying creams or squeezing the pustule.
The presence of a BCG scar is often used as a proxy indicator of successful vaccination, especially in resource-limited settings. However, the absence of a scar does not definitively mean the vaccine was ineffective, and routine revaccination is not recommended based on this alone.
What if? If a large abscess (greater than 1 cm) forms at the site, or if axillary lymph nodes become significantly swollen and drain pus (suppurative lymphadenitis), this is considered an adverse event following immunization (AEFI). The child must be referred for medical evaluation, as this is not a normal reaction.

How to Approach the Question

Identify the core of the question: It asks for the specific timeframe when the final scar from a BCG vaccine is formed.
This is a factual recall question based on knowledge of the national immunization schedule and vaccine reactions.
Mentally review the typical progression of the local reaction after an intradermal BCG injection.
Recall the stages in order: initial wheal -> papule -> pustule/ulcer -> healing and scar formation.
Assign the standard timeframes to each stage: papule (2-3 weeks), ulcer (4-6 weeks), and scar (6-12 weeks).
Compare the options provided with the correct timeframe for scar formation (6-12 weeks). '2 months' (approximately 8 weeks) falls directly within this range and is the best fit.

Concept Tested & Keywords

Concept Tested: Timeline of local reaction and scar formation after BCG vaccination.
Stem keywords: BCG vaccination, scar, formed
Lead-in keywords: After giving
Negative lead-in flag: false

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 42-44