A few years ago, I was sitting in traffic on a motorway when I started eating an apple. When I felt a familiar itching in my throat I ignored it – as usual. I’d long been aware that I was slightly allergic to them, but it had never been so bad that I’d given it much thought, or talked to a doctor. But that day, the itch gradually began to feel more like a swelling, and a constriction, of my throat. I was terrified. With no idea where the nearest hospital was, I panicked, frightened that the fruit allergy I’d been ignoring for years had suddenly evolved into full-on anaphylactic shock. As it turned out, I was wrong: within an hour or two I was fine, no EpiPen required. But it was enough of a scare that I’ve avoided eating apples since.
Although these days most people are familiar with nut allergies, few of us have needed to give the issue much thought. But the idea that a whole swathe of foods can cause dangerous reactions was brought into sharp relief by the death of Natasha Ednan-Laperouse, who was just 15 when she unknowingly ate sesame, to which she was allergic, in an incorrectly labelled baguette from Pret a Manger. Natasha’s parents are now campaigning to raise awareness of food allergies.
Scepticism about food allergies is perhaps a uniquely British tendency, rooted in the same category as the stiff upper lip and the desire not to ‘make a fuss’. Even the idea of Allergy Awareness Week, which starts tomorrow, might make some roll their eyes. Personally, I had never heard of a fruit allergy, so I didn’t take it seriously when, in my mid-20s, I started getting a tingling sensation in my mouth, little lumps on my lips and a tickly throat, every time I ate an apple.
With a two- or three-a-day habit, I turned a blind eye and accepted these symptoms as a necessary evil if I wanted to carry on eating apples. I switched to organic for a bit, thinking I might be reacting to pesticides, but when the symptoms continued, I continued to ignore them. Also, since I seemed to be able to eat cooked apples without a reaction, I half wondered if it was all in my mind.
It turns out that this kind of fruit allergy is surprisingly common. Dr Adrian Morris is an allergy consultant based at Surrey Allergy Clinic in London and Guildford. ‘There are two types of allergy to fruit,’ he explains. ‘The first is called silver birch pollen oral allergy syndrome and applies to 90 per cent of people who are allergic to apples and stone fruit. The symptoms are mainly a scratchy throat and itchy mouth. This type of allergy is caused by a reaction to one of the proteins in the fruit, called profilin, or PR-10.’
Although annoying, this allergy is harmless and doesn’t progress into anaphylaxis (which can be fatal), and profilin is easily damaged by heat, so cooked fruit will not be a problem.
Typically, says Dr Morris, most people with silver birch pollen oral allergy syndrome also experience hay fever in their teens and early 20s. Then the hay fever is replaced by an oral allergy. ‘Most people don’t put two and two together, but they are rooted in the same thing,’ he says, adding that hay fever affects about 30 per cent of the population. Of that, 20 per cent are allergic to silver birch pollen – and half of them, like me, get oral symptoms with raw fruit.
The second type of fruit allergy, called fruit anaphylaxis, is far more serious, and potentially fatal. ‘The same fruits that cause pollen oral allergy syndrome also contain another protein called Prup3, a lipid transfer protein which, in those who are allergic to it, causes a much more severe anaphylactic reaction, even when the fruit is cooked,’ says Dr Morris.
Confusingly, the severity of an allergy might not be obvious at first. This was the case for food writer Sally Davies, who first noticed a reaction to fruit when she was at university. ‘I started developing weird symptoms at the same time each morning,’ says Sally, now 50.
‘I would sweat, shiver and cough, and my hands and face, tongue and throat would become really itchy, but it would pass after an hour or so. Eventually I narrowed it down to the kiwi I was eating for breakfast every day, so I simply stopped eating it.’
For 25 years she avoided them, although if traces of kiwi had touched the same chopping board as something she ate, it would leave her mouth itchy. Then, a couple of years ago, she accidentally drank juice containing kiwi at a hotel. ‘They called a doctor and when he arrived I was on the bathroom floor, coughing and throwing up.
My face and hands had blown up and my throat was so swollen it was hard to breathe.’ An EpiPen injection calmed the reaction, and today, she’s extremely careful. ‘I was lax before that, partly because I had no idea that my allergy had got so much worse in the 20 years since I actually ate kiwi, and also because it’s a fruit that always seemed relatively easy to avoid. But after my recent experiences I’m much more paranoid, and think it’s probably time to get an EpiPen.’
Some people who experience anaphylaxis for the first time in adulthood assume that the allergy has only just started. But it’s actually very unusual for allergies to develop later in life – it’s much more likely that an existing allergy has just become more manifest.
‘They will have been slightly sensitised to the fruit in childhood then, if they eat a lot of it later in life, they could have a strong allergic reaction because more exposure ramps the allergy up a notch,’ says Dr Morris, who adds that while nut allergies and anaphylactic reactions in children are on the increase, that is not the case for fruit allergies. ‘It’s not that more people are developing fruit allergies, but we are just becoming more aware of them.’ If you’re in doubt about your reaction to fruit, pollen oral allergy syndrome is easily tested with a skin-prick test, and fruit anaphylaxis can be measured with a blood test.
The treatment for pollen oral allergy syndrome is called desensitisation or immune therapy: small amounts of the pollen are given to the patient over a period of three years. However, while this effectively treats hay fever symptoms, it only works with fruit allergies in 40 per cent of people.
Ironically, avoiding potential allergens altogether can have the opposite to the intended effect, and advice on how to prevent allergies has changed drastically over the past decade. Twenty years ago, allergy-prone families were advised not to give eggs to babies under three months, and to avoid nuts for the first three years. But today, the thinking has completely reversed.
‘Until 10 years ago, we discouraged nut exposure in young children under three, thinking we were protecting them – and inadvertently this error created a generation of nut-allergic children. In fact, a little bit of early exposure to allergens actually switches off allergies, whereas delayed exposure makes people more prone to them,’ says Dr Morris. We shouldn’t, for instance, be peeling apples for kids. ‘And they should eat peanut butter, play with a cat, and definitely get dirty.’
Cleanliness, it turns out, is not such a good thing after all.
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