Penicillin: millions of people wrongly labelled with allergy, experts warn

Millions of people wrongly think they are allergic to penicillin, which means they could take longer to recover after an infection, pharmacists say.

Around four million people in the UK have the drug allergy on their medical record - but when they were tested, 90% of them were not allergic, the research suggests.

The Royal Pharmaceutical Society (RPS) said patients should check their medical record the next time they visit their GP to ensure they are not wrongly labelled as allergic to the drug, which is used to treat infection.

The RPS says many people confuse antibiotic side-effects with an allergic reaction, which include itchy skin, a raised rash and swelling as well as nausea, breathlessness, coughing, diarrhoea and a runny nose.

But antibiotics, which treat bacterial infections, can themselves cause nausea or diarrhoea and the underlying infection can also lead to a rash.

Therefore people often mistakenly believe they are allergic to penicillin, which for many, are good, common antibiotics.

In addition, an allergy reported many years ago, perhaps in childhood, may have settled down but the perception of having an allergy remains.

A paper published in the British Journal of Clinical Pharmacology in 2019 suggested six to 10% of the general population in the UK and US are recorded as allergic to penicillin “although emergent research shows that 90–95% of these labels are found to be incorrect following comprehensive allergy testing”.

Other research published in the Journal of Antimicrobial Chemotherapy in 2019 estimated that incorrect penicillin allergy records affect 2.7 million people in England alone.

Compared with patients without a penicillin allergy record, those who have one have an increased risk of death, published data has suggested.

RPS spokeswoman Tase Oputu said: “Every medicine has benefits and harms and I urge patients to ask questions about a penicillin allergy label on their medical record.

“Many individuals are at low or very low risk of having a genuine penicillin allergy and we often find that after careful investigation that they can take penicillin safely.

“Others, who may have had a severe reaction in the past, will need allergy testing and in some cases may never be able to take penicillin.

“Patients should talk to their pharmacist or other health professional to help understand the difference between side effects and allergic reactions, which can sometimes look similar, so they receive the most effective treatment for their needs.”

Both the NHS and global health organisations are trying to cut the use of antibiotics owing to increasing antibiotic resistance (where strains of bacteria develop resistance to many different types of antibiotics).

The NHS website says many infections are caused by viruses, so antibiotics are not effective, while antibiotics are often unlikely to speed up the healing process and can cause side-effects.

It says antibiotics are no longer routinely used to treat chest infections, ear infections in children and sore throats.