When should a healthcare provider ask about a patient's allergies?

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Last updated: December 18, 2025View editorial policy

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When to Ask About Allergies in the Perioperative Setting

Allergy history must be obtained during the pre-operative assessment phase (Sign-in), well before the patient enters the operating room. 1

Correct Answer: A - Sign In

The WHO Surgical Safety Checklist designates the "Sign-in" phase as the critical time point for verifying allergy status before induction of anesthesia. 1 This occurs during pre-operative evaluation when the anesthesiologist reviews the patient's medical record and conducts a focused history. 1

Why Sign-in is the Only Appropriate Time

Pre-operative allergy assessment is mandatory because:

  • A thorough allergy history, including previous anaphylactic reactions, latex allergy, and drug allergies must be documented before any medications are administered 1
  • Approximately 8% of the population is sensitized to latex, with healthcare workers and children with spina bifida at particularly high risk 2, 3
  • One-third of patients with previous perioperative allergic reactions will experience recurrence if the culprit agent is not identified and avoided 2
  • Latex allergy should be recorded in case notes and on the patient's wrist bracelet before entering the operating theater 2

Why Other Options Are Wrong

Timeout (Option C) is too late because:

  • The patient has already been exposed to potential allergens during induction 1
  • Neuromuscular blocking agents, latex gloves, and chlorhexidine preparations may have already been used 2
  • Anaphylaxis during anesthesia has an incidence of 1/10,000 to 1/20,000 surgeries, with mortality of 3.5-4.8% 4, 5

Sign-out (Option B) and Postoperative (Option D) are completely inappropriate as the patient has already undergone full anesthetic exposure by these time points. 1

Specific Allergy Questions to Ask During Sign-in

Direct questioning should include: 2

  • Previous anaphylactic reactions during any medical procedure
  • Contact with balloons, condoms, or latex gloves causing itching, rash, or angioedema
  • Allergies to fruits (banana, chestnut, avocado) suggesting latex cross-reactivity
  • History of multiple surgical procedures, especially in childhood
  • Healthcare worker status or occupational latex exposure
  • Known drug allergies, particularly to antibiotics, neuromuscular blocking agents, or chlorhexidine

Critical Pitfall to Avoid

Never proceed with elective surgery if allergy history is incomplete or suggests previous perioperative reaction. 2 If a severe reaction occurred previously and the upcoming procedure is elective, the patient must be referred for specialized perioperative allergy investigation before surgery. 2 For emergency surgery with suspected allergy history, avoid all exposures that occurred before the previous reaction, and consider regional or inhalational techniques to minimize intravenous drug exposure. 2

References

Guideline

Pre-Operative Evaluation and Preparation

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Latex Allergy and Its Clinical Manifestations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Perioperative approach of allergic patients.

Best practice & research. Clinical anaesthesiology, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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