Hidden Operating Room Allergens: Dyes, Implants, Chlorhexidine Overwash

Underrecognized Exposures Complicate the Workup

Perioperative anaphylaxis often traces back to agents that never make it into the medical record. Kimberly Blumenthal, MD, MSc, a professor of medicine at the Mayo Clinic College of Medicine and Science, told HCPLive that surgical dyes, antibiotic-coated implantable devices, and latex exposure from a surgeon's gloves or an all-latex operating room are all potential culprits that are inconsistently documented, leaving allergists to reconstruct exposures after the fact.

Blumenthal singled out chlorhexidine gluconate, the disinfectant used to clean the skin before incision, as an emerging cause of perioperative anaphylaxis. She noted that patients are sometimes instructed to wash with chlorhexidine for several days before surgery and are washed again on arrival, a repeated-exposure pattern that can sensitize patients before they ever reach the operating room. A recent case report similarly describes chlorhexidine as increasingly recognized as a perioperative anaphylaxis trigger capable of producing both immediate and delayed hypersensitivity reactions after repeated antiseptic exposure.¹

The OR Is a Controlled Setting for Treatment

Once anaphylaxis is recognized, Blumenthal said the operating room is one of the safer places for it to occur.

“It's the safest place to have anaphylaxis,” she said. “Maybe the allergist office is equally safe, but the anesthesia room patients are either already intubated or can be intubated, so they can have their airway protected. They have lines…of access intravenously to be able to administer medications. Once it's detected, the treatment is very easy…because they have access to all the medicines that are needed.”

The anesthesia team has immediate access to epinephrine and vasopressors such as norepinephrine and phenylephrine, steroids, and antihistamines.

The harder problem is recognition. Blumenthal explained that surgical drapes can hide a rash, and hypotension has a broad differential that includes routine medication side effects rather than allergy. A recent narrative review of perioperative anaphylaxis echoed this diagnostic challenge, noting that cutaneous findings may be absent, delayed, or concealed by drapes while hypotension, bronchospasm, and desaturation can stem from multiple causes occurring within minutes of each other.² Even when treatment goes smoothly, a reaction typically forces the procedure to be rescheduled.

Counseling Patients Without a Confirmed Culprit

When testing fails to identify a cause, Blumenthal said allergists rely on what negative results are available. Negative skin tests to specific agents support using those drugs again, ideally with a test dose that introduces a small amount first, followed by observation before the remaining dose is given.

Where no culprit is confirmed, Blumenthal said allergists can still recommend an alternative agent based on which exposure seems statistically or clinically most likely, such as switching neuromuscular blocking agents to succinylcholine. She said this guidance, while imperfect, generally allows patients to proceed through subsequent surgeries safely.

Read part 1 of our interview with Blumenthal on common triggers of perioperative anaphylaxis here: What's Behind Perioperative Anaphylaxis? Cefazolin Tops the List

Blumenthal has no reported disclosures.

References

1. Sandoval Morales F, Pelletier F, Aubin F, Castelain F. Chlorhexidine-Induced Contact Anaphylaxis. Cureus. Published July 23, 2025. doi:10.7759/cureus.88598

2. Perioperative anaphylaxis: preparing for the next rocuronium, chlorhexidine, or antibiotic reaction. GlobalRPH. Published 2026. https://globalrph.com/2026/07/perioperative-anaphylaxis-preparing-for-the-next-rocuronium-chlorhexidine-or-antibiotic-reaction/