Four million Britons wrongly think they are allergic to penicillin… and it could be catastrophic. JOSA KEYES was one of them – and explains the crucial step you need to take now

Millions of people in Britain have a penicillin allergy label in their medical records and I am one of them. This means that the most effective treatment for a wide range of bacterial infections is not available.

You may think that this is not important and that many alternative antibiotics are equally effective. But you’d be wrong: Not only are antibiotics from the penicillin family often still the most valuable option, but they are also less likely to cause side effects than alternatives. So you really don’t want to rule them out unless you have a severe allergy.

Yet as many as nine in ten people (around four million of us) who think they are allergic to penicillin are not, according to the charity Antibiotic Research UK.

In fact, this 90 percent of us with a ‘penicillin allergy’ will actually have arisen from a reaction we had in childhood, or have had a reaction to penicillin specifically linked to having glandular fever (as in my case) , or have mistaken a side effect or unrelated symptom of an allergy.

A penicillin allergy is often self-diagnosed by people who have had symptoms, such as diarrhea, vomiting, nausea, headache, or bloating, while being treated with the medication. This ‘allergy’ is then added to their medical bills without testing or further questioning. And that’s where it usually stays.

The Royal Pharmaceutical Society reports that simply being labeled as allergic to penicillin is associated with a higher mortality rate of six additional deaths per 1,000 patients in the year after treatment for infection, because the drug saves lives that other drugs cannot.

The problem is, how do we ensure that those who are truly allergic keep the warning on their medical notes, while removing it for those who are not?

For the whole population, this ‘de-labelling’ has the potential to reduce unnecessary long hospital stays and hospital infections, saving the NHS money.

When Alexander Fleming, professor of bacteriology at the University of London, went on holiday in 1928, he had no idea the world-changing event that would unfold in his laboratory at St Mary’s Hospital, Paddington.

Back at work on September 3, he glanced at a moldy Petri dish in which he had grown Staphylococcus bacteria and noticed an unusually clear margin around the fluffy green spot.

Coincidentally, scientists in the same laboratory were studying the effects of fungi on the lungs, and a rare strain of Penicillium notatum – a fungus – had been transferred to Fleming’s dish, where it destroyed the infection-causing bacteria as quickly as possible.

Based on his findings, Fleming was awarded the Nobel Prize in 1945, when the new penicillin drugs – with their ability to treat previously fatal bacterial infections such as respiratory infections, syphilis and gonorrhea – became widely available.

The penicillin family remains the best treatment for many bacterial infections, although several antibiotic compounds have since been developed.

I was seventeen when I developed a chronic sore throat after visiting my thirteen-year-old cousin, who was in bed with glandular fever.

Our GP diagnosed tonsillitis and gave me repeat prescriptions for amoxicillin (a form of penicillin). I wasn’t getting better, so he gave me more.

Still feeling rough, I went to stay with a friend in Norfolk. The first morning I woke up with itchy, raised red bumps from head to toe. My friend’s mother, a general practitioner, examined me and had me tested. Glandular fever.

When I got home I went straight to bed and woke up very white and swollen, covered in small purple bruises. No one seemed concerned about this – it was the 1970s – and I gradually recovered.

Only recently did I understand what happened.

The National Institute for Health and Care Excellence reports: ‘Maculopapular rash (small red spots that coalesce into spots – which may look like hives, a symptom of allergy) is common with ampicillin and amoxicillin, but is usually unrelated to a true penicillin -allergy. They almost always occur in patients with glandular fever. Broad-spectrum penicillins should therefore not be used for the “blind” treatment (without testing for bacterial infections) of sore throat.’

In other words, the rash I got was not a symptom of a penicillin allergy, but a reaction to the drug associated with the mononucleosis virus.

There were no further antibiotic-related events in my life until 1992, when, six months pregnant with my second child, I developed a urinary tract infection. Since this can lead to premature labor, I was given an antibiotic – I’m not even sure which one.

Within hours I was covered in itchy red blobs that collected, especially uncomfortably over my bump. That’s it. I thought I was allergic and the label was applied.

It didn’t matter that the doctors hadn’t said that. I was convinced and determined never to use penicillin again.

Now that I’m in my sixties, I want to have access to the best possible treatment if the need arises. So I have to have the penicillin allergy label removed if it is not suitable.

In an effort to expedite this crucial de-labelling, the British Society for Allergy and Clinical Immunology has produced its 2022 guidelines for de-labelling services for penicillin allergy, for non-allergists working in hospitals.

Ideally, GPs will refer patients to a de-labelling clinic as soon as one becomes available, but Britain has the fewest allergists per capita in the developed world, hence the need to rely on non-specialists, says Dr Sophie Farooque, a consultant allergist at Imperial College Healthcare NHS Trust in London.

She and her colleagues recently set up one of the first such clinics. So far, the number of people who have had their tags removed is small, but the future potential is enormous. The clinic uses a two-pronged approach. First, the pharmacy team runs through a checklist, including a patient’s medical records.

For example, they may have been prescribed amoxicillin – without realizing that it belongs to the penicillin family – and had no problems.

Other questions will focus on symptoms that led to the initial labeling, such as nausea, type of rash, stomach pain, headache, or strange taste.

If the patient is considered low or no risk, he or she will be given a dose and kept under observation.

Patients in doubt are referred to Dr. Farooque’s clinic for further testing, including skin testing where small amounts of penicillin are injected under the skin to assess the response. The clinic is held on a day ward, allowing rapid treatment if a patient has an allergic reaction.

This won’t be a quick fix for the millions of people wrongly labeled as allergic to penicillin – although there are future plans for a national allergy strategy, says Dr Farooque.

In the meantime, if you have a penicillin allergy label on your notes that you think is incorrect, you can ask your GP to contact the Imperial de-labelling clinic, advises Dr Tom Swaine, infectious disease specialist at Imperial.

I will ask my GP to refer me once the clinic is fully operational, in case I ever develop the type of infection for which the penicillin family is the best treatment.