Who Needs An Allergy Test Before Anesthesia? 

Anesthetics and other medical equipment used while administering anesthesia can cause allergic reactions in patients with hypersensitivities, a.k.a. allergies. These allergic reactions are triggered by the immune system overreacting to a medicine or substance, similar to food-related allergies. Thankfully, severe allergic reactions during anesthesia are rare, with anaphylaxis occurring only in one per every 10,000-20,000 anesthesia cases (3). Patients who have a history of allergies to certain food groups and medications are at a higher risk of having an allergic reaction during anesthesia; as a result, they may benefit from an allergy test before anesthesia to evaluate potential risk. 

Patients with drug, seasonal, and other allergies are more likely to experience an allergic reaction related to anesthesia or other aspects of the procedure. For example, people allergic to tropical fruits are at higher risk of a latex allergy (2). Patients who have conditions such as atopy and spina bifida are also more likely to be allergic to latex (2). In many places, latex has been replaced by less allergenic materials; however, patients with known allergies that are linked to a higher risk should still discuss whether they need an allergy test with their doctors. 

Similarly, those who have an allergy to a specific pain medication or non-steroidal anti-inflammatory drug (NSAID) are likely to be allergic to similar classes of medications. Patients who have a type of food allergy called alpha-gal syndrome are more likely to be allergic to intravenous, gelatin-based colloids (2). 

Previously, the medical community worried that patients who are allergic to soy and egg were allergic to propofol, an intravenous medication used during anesthesia. Propofol is mixed in a liquid that is partly composed of soybean oil and egg lecithin. However, research has demonstrated that people with egg and soy allergies can safely receive propofol during procedures (2). Those who are allergic to soy and egg are allergic to proteins in the foods, and the soybean oil and egg lecithin used in propofol only contains trace amounts of residual protein at most. Other patients, however, may be allergic to propofol itself, regardless of whether they have an allergy to eggs or soy (2). 

Muscle relaxants called neuromuscular blocking agents (NMBA) are some of the most common triggers of anesthesia-related allergic reactions, followed by latex and antibiotics (5). The number of cases of allergic reactions to less common allergens such as vital dyes, NSAID drugs, and intravenous colloids is increasing (4). As a result, patients should be thoroughly evaluated preoperatively to determine their risk of allergic reactions during anesthesia. Anesthesia logs and medical history charts can be helpful tools to preoperatively assess a patient’s level of risk for anesthetics, latex, and other drugs (5). Based on their history, a skin allergy can provide further evidence to mitigate the risk of allergic reactions during anesthesia if a patient’s suspected allergens are known (5). 

References 

1. Beyaz, Sengul. “Evaluation of skin test indications for general anesthetics in real life: a prospective cohort study,” Brazilian Journal of Anesthesiology (English Edition), vol. 72, no. 3, May-June 2022, pp. 350-358. doi: 10.1016/j.bjane.2021.07.005 

2. Dewachter, Pascale et al. “Anaesthetic management of patients with pre-existing allergic conditions: a narrative review.”British Journal of Anesthesia, vol. 123, no. 1, pp. E65-E81, July 2019. doi: 10.1016/j.bja.2019.01.020 

3. Dewachter, Pacscale et al. “Anaphylaxis and Anesthesia: Controversies and New Insights.” Anesthesiology, Nov 2009, vol. 111, pp. 1141-1150. doi: 10.1097/ALN.0b013e3181bbd443 

4. Mertes, Paul M et al. “Hypersensitivity reactions in the anesthesia setting/allergic reactions to anesthetics.” Current opinion in allergy and clinical immunology, 2012, vol. 12, no. 4, pp. 361-368. doi:10.1097/ACI.0b013e328355b82f 

5. Pfutzner, Wolfgang and Knut Brockow. “Perioperative drug reactions — practical recommendations for allergy testing and patient management.” Allergo Journal International, 2018, vol. 27, no. 4, pp. 126-129. doi: 10.1007/s40629-018-0071-1 

6. Savic, L et al. “Allergy and anesthesia: managing the risk.” BJA education, 2020, vol. 20, no. 9, pp. 298-304. doi:10.1016/j.bjae.2020.04.005