Assessing allergy

Background

The goal of pre-operative assessment here is to identify true allergy. If a patient mentions that they are allergic to a substance or material that they may encounter during the perioperative period, this must be explored and a concerted effort made to differentiate an episode of anaphylaxis (i.e. a true allergy) from sensitivities and side effects.

Anaphylaxis can be a life-threatening reaction that happens suddenly, without warning and can affect anyone. Low blood pressure, impaired circulation and lack of oxygen in the lungs combine to starve the tissues of oxygen, leading to shock which in extreme cases rapidly progresses to cardiac arrest or even death1. It is immunologically mediated, with respiratory or circulatory effects that develop over minutes and is often associated with skin or mucosal changes.

Common perioperative precipitants

There are several common triggers that a patient is likely to encounter during the perioperative period2:

  • Antibiotics

    • co-amoxiclav

    • teicoplanin

    • cefuroxime

  • Neuromuscular blocking agents

    • rocuronium

    • atracurium

    • suxamethonium

  • Others

    • chlorhexidine

    • blue dye

    • colloids

Symptoms consistent with anaphylaxis

If a patient communicates that they have an allergy, explore the issue.

  • ask what the nature of the reaction was, in particular:

    • how shortly after exposure did the reaction (NB <1hr is consistent with anaphylaxis)

    • was there swelling of their airway/did their throat ‘close up’?

    • did they become short of breath? did their voice become wheezy?

    • did they become pale and clammy? did their blood pressure drop to a low level?

    • did they become disoriented?

    • did they develop a rash or hives?

  • ask if the allergy has ever been formally tested by an immunology centre3

  • ask if they had to be hospitalised

  • ask if they have ever been exposed to the substance again, and what happened

Outcome

The goal should be to elucidate whether their reaction falls into one of the following categories:

  1. true and confirmed anaphylaxis/allergy
  2. history consistent with true anaphylaxis but unconfirmed
  3. likely sensitivity or side-effect

References

1.
Manian DV, Volcheck GW. Perioperative Anaphylaxis: Evaluation and Management. Clinical Reviews in Allergy & Immunology. 2022;62(3):383-399. doi:10.1007/s12016-021-08874-1
2.
Harper NJN, Cook TM, Garcez T, et al. Anaesthesia, surgery, and life-threatening allergic reactions: epidemiology and clinical features of perioperative anaphylaxis in the 6th National Audit Project (NAP6). British Journal of Anaesthesia. 2018;121(1):159-171. doi:10.1016/j.bja.2018.04.014
3.
Volcheck GW, Hepner DL. Identification and Management of Perioperative Anaphylaxis. The Journal of Allergy and Clinical Immunology In Practice. 2019;7(7):2134-2142. doi:10.1016/j.jaip.2019.05.033