When Did an Allergy Become Anything We Don’t Like?
“I’m allergic to lentils.”
What actually happens when you eat lentils?
“I don’t like them.”
Then you are not allergic to lentils.
You don’t like lentils.
There is an important difference.
And before anyone assumes that the examples in this article are invented for comic effect, they are not.
The examples discussed here are drawn from actual patients and actual allergy histories encountered in clinical practice.
That includes patients recorded as being allergic to:
oxygen
adrenaline
and even
“anaesthetics.”
These are not fictional examples designed to make a point. They are exactly the reason the point needs making.
Somewhere along the way, the word allergy appears to have acquired a completely new public meaning. It can now apparently mean:
I don’t like it.
It made me feel a bit funny.
It upset my stomach once.
I developed a headache.
My heart started beating faster.
I felt sick.
My mother told me I was allergic to it when I was six.
Or simply:
I would rather not have it.
But an allergy is not a synonym for an unpleasant experience.
It has a clinical meaning.
What is an allergy?
In straightforward terms:
An allergy is an abnormal immune response to a trigger.
The important words there are immune response.
Your body responding to something does not automatically make that response an allergy.
Your heart beating faster after receiving a drug does not automatically indicate allergy.
Feeling nauseated does not automatically indicate allergy.
Something tasting unpleasant certainly does not indicate allergy.
An adverse effect is not automatically an allergy.
An intolerance is not automatically an allergy.
A dislike is definitely not an allergy.
That distinction ought to be fundamental to taking an allergy history.
Unfortunately, it is sometimes lost somewhere between:
“Are you allergic to anything?”
and somebody placing an allergy wristband around a patient’s arm.
The Allergy Wristband Is Not a Shopping List
An allergy wristband is a patient-safety device.
What is written on it can influence prescribing, drug administration, anaesthesia and emergency treatment.
That means the healthcare professional completing it has a responsibility to do rather more than simply copy whatever word comes out of the patient’s mouth.
And again, the examples that follow are not hypothetical.
They come from real clinical encounters.
“You’re Allergic to Oxygen?”
One of the more memorable examples occurred in theatre.
The patient had oxygen recorded as an allergy.
That immediately required a conversation.
As healthcare professionals, we do not simply have a duty to record information. We also have a duty to educate patients when their understanding of that information is clearly wrong or potentially unsafe.
So I asked what they meant by being allergic to oxygen.
I then pointed out something rather fundamental:
Room air contains approximately 21% oxygen.
In other words, if they were genuinely allergic to oxygen itself, sitting there breathing normally presented something of a conceptual difficulty.
Their response was wonderfully dismissive:
“That’s obviously why I always feel so giddy!”
And there, in one sentence, is part of the problem.
Instead of the explanation correcting the misconception, the misconception simply absorbed the explanation and became further “evidence” for itself.
The reasoning had effectively become:
I sometimes feel giddy.
There is oxygen in the air.
Therefore the oxygen must be causing the giddiness.
But that is not how allergy works.
Oxygen is not some unusual pharmaceutical substance introduced into the body from nowhere.
We breathe it continuously.
It is present in the atmosphere around us.
It is essential to normal aerobic cellular metabolism.
The patient may genuinely have felt giddy at times.
That does not make the symptom imaginary.
But it also does not establish an immune-mediated allergy to oxygen.
That is where professional responsibility comes in.
The correct response is not to ridicule the patient.
Nor is it to shrug and write OXYGEN ALLERGY on the wristband.
It is to explain the physiology, clarify the history and establish whether the patient actually reacted to something associated with oxygen administration.
Was oxygen delivered through a mask?
Was adhesive involved?
Was there a nasal cannula?
A cleaning agent?
A humidification system?
Did the patient become anxious while oxygen was being administered?
Was there another substance present at the time?
Or had somebody, somewhere along the clinical journey, simply attached the word allergy to an unpleasant experience without ever asking the next question?
That is the point.
A healthcare professional has a duty not merely to record what a patient believes, but where appropriate to challenge an obvious misconception with accurate clinical information.
Education is part of patient care.
If a patient believes they are allergic to something fundamental to human physiology, simply perpetuating that belief in the clinical record is not being respectful.
It is potentially embedding misinformation.
And in an anaesthetic environment, the distinction is hardly trivial.
Oxygen is fundamental to anaesthetic practice and to maintaining life.
If something as extraordinary as oxygen allergy appears on an allergy wristband, a registered clinician should stop and establish exactly what is meant before allowing that label to travel any further through the patient’s medical record.
“I’m Allergic to Adrenaline”
Another genuine example was:
“I’m allergic to adrenaline.”
Again, surely the next question should be:
“What actually happened?”
If the answer is:
“My heart raced, I started shaking and I felt anxious,”
then we have just described some of the entirely predictable effects of adrenaline.
That history needs clarification before ADRENALINE ALLERGY is uncritically written across an allergy wristband.
Adrenaline is also particularly important because it is an endogenous hormone and one of the principal mediators of the human fight-or-flight response.
More importantly in the context of allergy itself, adrenaline is the first-line emergency treatment for anaphylaxis.
An inaccurate allergy label therefore has the potential to create uncertainty at exactly the moment when treatment needs to be immediate and unambiguous.
And Then There Is “Anaesthetics”
And then there is perhaps the most extraordinary example:
“Allergic to anaesthetics.”
Again, this is an actual documented patient history.
Which anaesthetic?
Propofol?
Sevoflurane?
A neuromuscular blocking agent?
An opioid?
A local anaesthetic?
An antibiotic administered during anaesthesia?
Chlorhexidine?
Latex?
An excipient?
Something else entirely?
Writing ANAESTHETICS on an allergy wristband is about as clinically useful as writing:
“ALLERGIC TO MEDICINE.”
It identifies neither the suspected allergen nor the reaction.
Ask the Bloody Question
A registered healthcare professional does not need to conduct a complete allergy investigation at the bedside.
They do, however, need to ask some very basic questions.
What were you given?
What happened?
How quickly did it happen?
What symptoms did you experience?
Have you had it before or since?
Was the reaction investigated?
Were you actually told by a clinician that you had an allergy?
That is not excessive interrogation.
That is basic clinical history taking.
The phrase:
“Patient says they are allergic to it”
should be the beginning of the history.
It should not be the end of it.
Real Allergies Matter
None of this is an argument for dismissing allergies.
Quite the opposite.
A genuine allergic reaction can produce urticaria, angioedema, bronchospasm, hypotension and potentially life-threatening anaphylaxis.
That is precisely why the word should mean something.
If everything from anaphylaxis to “I don’t like lentils” gets deposited into the same conceptual box labelled ALLERGY, we degrade an extremely important piece of clinical information.
The correct response to widespread misuse of the word allergy is therefore not to take allergy less seriously.
It is to take it more seriously.
Cross-Reactivity: Where Taking the History Properly Matters
There are genuine relationships that may not initially be obvious.
Latex allergy provides a good example.
Some people with genuine latex allergy can cross-react with proteins in particular fruits and foods.
Banana, avocado, kiwi and chestnut are among the recognised associations.
That is useful clinical information.
A nurse, doctor, ODP or other practitioner hearing a convincing history of latex allergy should therefore understand that apparently unrelated questions about food reactions may actually have clinical relevance.
This is where knowledge matters.
But it is also where inherited clinical folklore can get us into trouble.
Shellfish, Iodine and a Myth That Refuses to Die
For many years an association between shellfish allergy and iodine became embedded in both public and healthcare thinking.
The logic went something like this:
Shellfish contain iodine.
Contrast agents contain iodine.
Therefore somebody allergic to shellfish must be allergic to iodine and therefore at increased risk from iodinated contrast.
It sounds superficially plausible.
It is also wrong.
Shellfish allergy is caused by an immune response to proteins in shellfish, particularly proteins such as tropomyosin.
It is not an allergy to iodine.
This is worth acknowledging because it demonstrates something healthcare professionals occasionally dislike admitting:
We can inherit incorrect information too.
Repeating something for thirty years does not transform it into immunology.
And I Stand Corrected on Propofol
I had myself remembered a historical association between propofol and peanut oil.
That recollection was incorrect.
And that correction belongs in an article about incorrect allergy beliefs.
Early propofol was formulated using Cremophor EL, a castor-oil-derived solubilising agent.
Problems with that formulation contributed to development of the later lipid formulation familiar to modern anaesthetic practice, containing soybean oil and egg phosphatide.
It was not originally a peanut-oil emulsion.
That is important.
Because there would be something spectacularly hypocritical about writing an article criticising people for repeating inaccurate allergy information while refusing to correct inaccurate allergy information of my own.
Clinical knowledge should work like that.
Evidence changes the answer; professional pride should not prevent the answer changing with it.
The Patient Can Be Completely Truthful and Still Be Wrong About the Diagnosis
This distinction is important.
If a patient says:
“That drug made me feel terrible.”
I believe them.
If they say:
“Every time I take it I vomit.”
That information matters.
If they say:
“It gives me severe diarrhoea.”
Again, clinically relevant.
But none of those statements automatically establishes an allergy.
The symptoms may be entirely genuine while the patient’s explanation for them is incorrect.
Correcting somebody who describes an adverse reaction as an allergy does not necessarily mean telling them:
“You imagined it.”
It means saying:
“I believe that happened. Now let’s establish what actually caused it.”
That is an enormous difference.
Registered Professionals Have to Think
This brings us to the uncomfortable part.
Registered healthcare professionals are not employed merely as transcription services.
Professional registration implies knowledge, judgement and clinical reasoning.
So when I have personally encountered real patients with entries such as:
OXYGEN
ADRENALINE
or
ANAESTHETICS
recorded as allergies, I inevitably start asking questions about the quality of the history that produced the entry.
Not because every unusual allergy history must be wrong.
Medicine has more than enough unusual immunological phenomena to teach us humility.
But because an extraordinary or nonspecific allergy claim should prompt more questions, not fewer.
The safe response to an improbable allergy is not:
“That is ridiculous.”
Nor should it be:
“Okay, I’ll write it on the wristband.”
It is:
“Tell me exactly what happened.”
That is clinical reasoning.
And sometimes the next step is:
“Let me explain why that probably isn’t an allergy.”
That is patient education.
The Wristband Can Cause Harm as Well as Prevent It
An inaccurate allergy label is not necessarily harmless.
Once something is entered into the clinical record, it can follow a patient for years.
The original story gradually disappears.
“Patient vomited after Drug X in 1997” becomes:
DRUG X — ALLERGY.
Eventually nobody knows why.
Now imagine that same process involving:
ADRENALINE.
Adrenaline is the first-line emergency treatment for anaphylaxis.
An unqualified allergy label therefore is not merely semantically irritating.
It can create uncertainty at precisely the moment when clinicians require clear information.
That is why allergy documentation deserves considerably more thought than:
Patient said it, therefore I wrote it down.
“I Reacted to It” Does Not Mean “I’m Allergic to It”
Perhaps the entire subject can be reduced to one sentence:
An allergy is not “my body reacted to it.” An allergy is “my immune system reacted to it abnormally.”
That distinction should be understood by healthcare professionals and, ideally, explained to patients.
Don’t like lentils?
Fine.
Don’t eat lentils.
They make you feel bloated?
Worth discussing.
Develop urticaria, facial swelling and bronchospasm shortly after eating them?
Now we have a history that demands proper investigation for allergy.
The words matter because the underlying mechanisms matter.
Take Allergies Seriously Enough to Get Them Right
Genuine allergy deserves respect.
Anaphylaxis deserves respect.
Patients with genuine allergies deserve healthcare professionals who understand their significance.
But that same respect demands that we stop treating the word allergy as a miscellaneous storage cupboard for every undesirable response anybody has ever experienced.
We should challenge questionable entries.
We should differentiate adverse effects from allergy.
We should correct historical myths.
We should document the actual reaction.
We should educate patients when necessary.
And when our own understanding proves incorrect—as mine did regarding the historical formulation of propofol—we should correct that too.
Science is not damaged by being corrected.
It depends upon it.
Perhaps the next time somebody says:
“I’m allergic to that,”
the most important clinical response is not reaching immediately for the allergy wristband.
It is asking one very simple question:
“What actually happens when you have it?”
Because the purpose of an allergy wristband is to prevent harm.
It is not a permanent home for every unpleasant sensation a patient has ever experienced after eating a food or receiving a drug.
