Latex allergy — formative SAQs

SAQ 1 — Intraoperative latex anaphylaxis (10 marks)

A five-year-old with myelomeningocele and a ventriculoperitoneal shunt develops generalised urticaria, wheeze and hypotension 40 minutes into an elective orthopaedic procedure. No new drug has been administered since induction 40 minutes earlier. [12]

Questions

1. What is the most likely diagnosis, and which feature in the history distinguishes it from drug-triggered anaphylaxis? (3 marks) [12]

2. Outline the immediate resuscitation and the investigation pathway after the event. (4 marks) [15]

3. Describe the long-term management and the institutional precautions for this child. (3 marks) [5] [11]

Model answer

Diagnosis and distinguishing feature (3). This is intraoperative anaphylaxis to natural rubber latex, the classic scenario for a child with spina bifida (historically 30 to 70 per cent sensitised). The distinguishing feature is the delayed onset — 30 to 60 minutes into surgery, reflecting mucosal absorption of latex protein via the peritoneum or surgical wound. Drug-triggered anaphylaxis (neuromuscular blockers, antibiotics, induction agents) fires within minutes of administration at induction. The spina bifida history and the delayed timing make latex the leading diagnosis. [12]

Resuscitation and investigation (4). This is anaphylaxis — a clinical diagnosis. Give IM adrenaline into the anterolateral thigh first (roughly 0.01 mg/kg of 1:1000, or a weight-banded autoinjector: 0.15 mg at her weight); call for help; lie flat with legs elevated if shocked; high-flow oxygen and IV fluids for hypotension; bronchodilator adjunctive for wheeze. Repeat adrenaline at five minutes if no response. Remove all latex from the environment and eliminate powdered latex gloves from the entire operating suite. After the event, follow the perioperative anaphylaxis pathway: serial serum tryptase at 1 to 2 hours, 4 hours, and baseline at follow-up; refer to an allergy specialist; and document the latex-safe requirement in the anaesthetic and surgical notes. [15]

Long-term management (3). Strict latex avoidance for life: latex-free gloves, catheters, and devices; avoid balloons, rubber bands, and latex-containing household items. Latex-safe surgery protocol for all future procedures: first case of the day, latex-free operating room, removal of all powdered latex gloves from the suite, and latex-free equipment. Provide a written anaphylaxis action plan (ASCIA/BSACI/FARE), a weight-banded adrenaline autoinjector, and medical alert identification. Notify the school, dentist, and all treating clinicians. Confirm the diagnosis with skin-prick testing, serum latex-specific IgE, and component-resolved diagnostics (Hev b components). Counsel on latex-fruit syndrome foods (banana, kiwi, avocado, chestnut). [5] [11]

SAQ 2 — Component-resolved diagnostics in latex allergy (10 marks)

A seven-year-old with spina bifida has positive serum latex-specific IgE but no clinical reaction history. Component-resolved diagnostics shows sensitisation to Hev b 8 (profilin) only, with no reactivity to Hev b 1, Hev b 3, Hev b 5, or Hev b 6.01. The parents ask whether she needs latex-safe surgery for an upcoming procedure. [8] [10]

Questions

1. How does Hev b 8 differ from Hev b 1, 3, and 5 in terms of clinical relevance? (3 marks) [8]

2. What does the Quercia 2009 study suggest about surgery in Hev b 8-monosensitised patients? (3 marks) [10]

3. Outline the broader management considerations for this child, including the role of component testing and the risk of over-restriction. (4 marks) [5] [8]

Model answer

Component clinical relevance (3). Hev b 1 (rubber elongation factor), Hev b 3, and Hev b 5 are genuine sensitising allergens with high clinical relevance — they indicate true latex allergy with anaphylaxis risk. Hev b 1 and Hev b 3 are dominant in spina bifida patients who have direct mucosal contact with raw latex particles. Hev b 8 (profilin) is a ubiquitous actin-binding protein shared across pollens and plant foods, so sensitisation often represents broad cross-reactive pollen sensitisation rather than genuine latex allergy. It typically carries low clinical reactivity. [8]

Quercia 2009 implication (3). The Quercia study showed that patients monosensitised to Hev b 8 (profilin) may safely undergo major surgery in a normal, non-latex-safe environment. This supports the component-guided approach: a child with only Hev b 8 positivity and no clinical reaction history may not need full latex-safe precautions, unlike a child sensitised to Hev b 1, 3, or 5. However, this decision should be made by an allergy specialist, weighing the component data against the clinical history and the child's risk profile (in this case, spina bifida). [10]

Broader management (4). Component-resolved diagnostics prevents both under-diagnosis and over-restriction. Over-labelling based on Hev b 8 alone causes unnecessary latex avoidance, surgical over-precaution, and family anxiety — a recognised pitfall. For this child with spina bifida (high-risk background), specialist assessment should weigh the Hev b 8-only result against her cumulative surgical exposure and the risk that genuine sensitisation to Hev b 1 or 3 has not yet developed. If the specialist confirms low clinical risk, standard surgical precautions may suffice, but latex-safe protocols remain the default for spina bifida until the assessment is complete. Provide latex avoidance education, counsel on latex-fruit syndrome, and arrange periodic review because sensitisation patterns can evolve. [5] [8]

References

1. [1]Arasi S, Barni S, Caminiti L, et al Latex Allergy in Children. J Clin Med, 2023.PMID 38202131
2. [5]Meneses V, Parenti S, Burns H, et al Latex allergy guidelines for people with spina bifida. J Pediatr Rehabil Med, 2020.PMID 33285646
3. [8]Ebo DG, Hagendorens MM, De Knop KJ, et al Component-resolved diagnosis from latex allergy by microarray. Clin Exp Allergy, 2010.PMID 20210809
4. [10]Quercia O, Stefanini GF, Scardovi A, et al Patients monosensitised to Hev b 8 (Hevea brasiliensis latex profilin) may safely undergo major surgery in a normal (non-latex safe) environment. Eur Ann Allergy Clin Immunol, 2009.PMID 19877563
5. [11]Allmers H, Schmengler J, Skudlik C Primary prevention of natural rubber latex allergy in the German health care system through education and intervention. J Allergy Clin Immunol, 2002.PMID 12170275
6. [12]Gold M, Swartz JS, Braude BM, et al Intraoperative anaphylaxis: an association with latex sensitivity. J Allergy Clin Immunol, 1991.PMID 2005317
7. [15]Simons FE, Ardusso LR, Dimov V, et al World Allergy Organization Anaphylaxis Guidelines: 2013 update of the evidence base. Int Arch Allergy Immunol, 2013.PMID 24008815