One of the things we do in the OR in the name of patient safety is the "time out". This is not sending the surgeon to sit in the corner for 5 minutes although that would not necessarily be a bad thing. What we do in the timeout is before the surgeon cuts skin, a nurse reads out what the patient has actually signed the consent for, what side we are operating on and what allergies the patient had.
A few weeks ago I put a lady to sleep for a D+C. She had a few allergies which the nurse read out including epinephrine. "Let me guess", said the surgeon," it makes her heart beat fast". "Yes", said I who had actually talked to the patient, "that is what happened to her". And we had a good laugh. And as I told the surgeon, this is not the first epinephrine allergy I have seen in my career.
Of course we all know what probably happened. She went to the dentist and a little local with epi went into a vessel, she got tachycardic and the dentist instead of saying mea culpa, told her she was allergic to epinephrine. And it goes on her chart.
I barely understand immunology, histamine or IgE so I don't really expect patients to understand allergies either. What we in the medical field have failed to explain to patients is the difference between an allergy to a drug which means you must never ever have the drug again and an adverse reaction which means you may not want to have the drug again but can have.
An important distinction with patients "allergic" to local anaesthetics after misadventures in the dental chair, to penicillin because they got a yeast infection, to anaesthetics because they got sick. All these go on the chart however as if they really were allergies.
My personal favourite is the patient who came to the OR which a lactose "allergy" who requested she not be given Ringer's lactate. I tried to explain that while I normally used normal saline, that lactate and lactose had very little in common and that she could if necessary get Ringer's lactate. She was however adamant and probably still tells the story of the stupid anaesthesiologist who wanted to give her Ringer's lactate even though she told him she was allergic to lactose.
We also have the "latex allergy. I don't doubt for a second that some patients have a true anaphylactic reaction to latex. Most of the latex allergies however are patients who got a rash from wearing rubber gloves or as one patient when I asked what happenned with latex told me, "we were just told avoid it as a precaution". When I did this last patient, the surgeon yelled at me because I used a latex penrose drain over his gown in order to start his IV.
As more of our supplies are now latex free (at probably considerable extra cost) this is less of the problem. When I worked at the CofE, latex allergy meant stripping the room of everything that could possibly have ever come into contact with latex. On several occasions the casual mention by the patient that he might be allergic to latex on entering the room resulted in having to discard the entire set-up for a latex free set-up delaying the start of the case by up to an hour.