MY LIFE’S IN DANGER FROM AN ALLERGY
— but no one can tell me what it is
After dutifully using the supplied hand sanitiser in a shop last summer, emma Bennett’s hands started swelling, becoming noticeably bigger as well as incredibly itchy within minutes.
the 42-year-old fitness instructor had been shopping alone when she experienced what she knew were the tell-tale signs of an allergic reaction. But when she asked the shop manager to see the sanitiser ingredients, she found none of her known allergens listed.
this was not the first time emma had suffered an unexpected reaction. In fact, for years it had happened every few months with unknown triggers.
Yet endless visits to doctors failed to provide a conclusive answer to what emma was allergic to — a condition known as idiopathic (i.e. no known cause) allergy. In emma’s case, this results in life-threatening reactions that affect the respiratory system within minutes.
from the age of seven, emma — who lives in Bolton with her husband Stephen, 49, a software engineer, and their son Seon, 11 — has experienced allergic reactions with no obvious cause, which sometimes become life-threatening.
Her first memories of the condition include waking up with red, itchy rashes across her chest.
‘At times the rash would come on three or four times a week, but back then it was not really anything you talked about,’ she says.
In another attack, when she was about 15, she went into full anaphylactic shock, again without any obvious cause (known as idiopathic anaphylaxis).
Anaphylaxis is a life-threatening reaction, where the immune system goes into overdrive.
following this, the body releases powerful chemicals called histamines, initially causing hives, difficulty breathing, abdominal pain, and swelling of the mouth and tongue. these also rapidly lower blood pressure by widening blood vessels, which can cause loss of consciousness.
Alarmingly, however, in some cases anaphylaxis can occur without an allergic cause.
Over the years, doctors advised emma that her reactions could be triggered by a variety of factors — even the sun — but nothing was ever proven.
It is not that there is no cause, explains Dr Shuaib Nasser, a consultant in asthma and allergic disease at Cambridge University Hospitals, it’s just we haven’t been able to find it yet.
‘Idiopathic simply means that you haven’t defined the cause — all anaphylaxis has a cause whether we are able to recognise it or not,’ he says.
‘It might be that it’s an allergic cause that hasn’t been identified — or that it is a non-allergic cause, such as specific hormone interactions in the body.’
Although many people experience minor symptoms of an allergic reaction without a clear cause, such as a rash, a lot fewer have severe idiopathic anaphylaxis.
It’s not clear exactly how many are affected by the condition, ‘but we know it accounts for about a quarter of anaphylaxis in adults’, says Dr Pamela ewan, a consultant allergist at Addenbrooke’s Hospital in Cambridge.
(Although if patients were to undergo the extensive testing for triggers in the future, Dr Nasser suggests that it is likely the number with genuine idiopathic anaphylaxis would be much lower.)
emma had a diagnosis breakthrough when she was on a first-aid course in her 20s. ‘After doing CPR on the mannequin, I went into full-blown anaphylaxis and became unconscious within a few minutes,’ she recalls. ‘Luckily, doctors had given me an adrenaline auto-injector, an epiPen, a couple of years earlier.
SOmeONe injected me and then I was taken to hospital. this led to my first specific allergy diagnosis — to latex.’ A few years later, emma was also found to be allergic to kiwi, after eating the fruit and quickly having an anaphylactic reaction, and has since been told she also has an allergy to some opioid painkillers such as morphine and codeine.
However, many of her reactions since, both mild and severe, are still without an identified cause.
throughout her 20s and early 30s, she had numerous reactions including one unnerving experience when in the supermarket with Stephen.
‘I just felt really, really unwell all of a sudden,’ she says. ‘I said to Stephen, “Something is not right, my hands are itchy and swollen.” I could feel it in my chest and I was clearing my throat a lot. We went straight to the hospital.’
Stephen, her parents and even her young son are epiPen-trained. (the injections have instructions on the side so anyone can use it when needed, but family members are often trained.)
the adrenaline injection helps to reverse the symptoms of anaphylaxis — tightening the dilated blood vessels and increasing blood pressure.
Similarly, the hormone helps relax tightened muscles in the airway that make it hard to breathe (this should alleviate the symptoms, but patients are advised to go to hospital immediately after use for monitoring).
It is very unusual for patients to experience anaphylaxis that is both idiopathic at times, yet also has an identified allergic trigger — as in emma’s case.
Concerns about idiopathic anaphylaxis were raised after two such reactions to Pfizer’s Covid vaccine in December 2020.
these concerns have led to recent guidance from the Government for caution before using the jab, for anyone with a known allergy to any of its ingredients — notably polyethylene glycol (PeG), a plastic-based compound used in many drugs and healthcare products.
the advice adds that special precautions should be taken with patients due to receive the vaccine who have a history of idiopathic anaphylaxis, including discussing the inoculation with an allergy specialist first and considering the possibility of a PeG allergy.
However, Dr Nasser says allergies to PeG are very rare, and not there in ‘the vast majority’ of idiopathic anaphylaxis patients.
many with the condition will be taking a daily antihistamine to manage symptoms. emma has been on different antihistamines over the years because the body gets used to them.
‘I am very cautious — playing it safe all the time,’ says emma. ‘It’s very scary but one of those things you get used to.’