Are We Overreacting to Allergies? A Closer Look at the Data and the Hype

Read some commentary, online especially, and it’s tempting to conclude that children are suffering from allergies at record rates. There is talk of an ‘epidemic’, of ‘huge rises’ in rates of severe allergic reactions. ‘The world is becoming more allergic to food,’ the BBC has reported. In the UK recently there was a national uproar when a young girl died from her allergy when, despite instructions from her parents, a coffee shop gave her a drink with traces of milk.

But the picture for allergies – when your immune system has a hyper-sensitive response to an otherwise harmless substance, resulting in asthma and eczema, and the need to avoid foods the likes of milk, but also peanuts, tree nuts, eggs, wheat, soy and shellfish – is anything but clear. Take, for example, the results of a scientific consensus study published late 2021 suggesting that infants are being wildly over-diagnosed as having a milk allergy – and consequently perhaps prescribed special milk formula – when their symptoms are normal for infants. 

‘Actually, around one percent of infants have a milk allergy and yet the amount of formula prescribed is 10 times what you would expect – that gives you an idea of the scale of the problem,’ argues Dr. Hilary Allen, milk allergy specialist and co-author of the study (the first not to be funded by the formula milk industry, on which more later).

Evidence suggests that there is over-diagnosis of other food allergies too, and of asthma and of penicillin allergy; some 10 per cent of US residents have been labeled allergic to penicillin, but data now suggests that as few as 10 per cent of that 10 per cent actually are. The worrying buzz around allergies is fuelled by increases in hospital visits, specialist clinics and prescriptions – not, in other words, by actual changes in human biology. 

The Allergy Hysteria

The panic is very real – one 2016 study trumpeted, somewhat implausibly, that by 2025 half of the entire population of the EU will suffer from chronic allergic diseases. And the consequences of this undue panic are very real too. For milk sometimes there is the burden of eliminating dairy from the mother’s diet, which is often advised, and the undermining of confidence in breast-feeding – so disrupting mother-baby bonding, with a detrimental impact on society at large; likewise nut allergies, for example, disrupt schools, airlines and restaurants.  

With food allergies especially very much a younger person’s issue, mis-diagnosis can lead to them having inappropriate restrictions to diets and activities, undue anxieties and emotional burdens, the excessive medicalisation of large parts of their childhoods and disrupt the work productivity of their parents too, argues Dr. Robert Boyle, clinical reader in paediatric allergy at Imperial College, London.

First off, what is actually happening? Do we face a global allergy catastrophe, as is often made out in the media? Are rates of allergy really rapidly on the rise? According to Professor Adam Fox, consultant paediatric allergist at Guy’s and St. Thomas’ Hospital, London, a conflicting picture is down to conflicting data. Some of this data – such as an Imperial College study published this September – suggests allergy rates are on the up. Other data – from, for example, a recent study of comparative periods over the last 20 years – say they’re not.

‘The conventional wisdom is that yes there are more people with allergies. Ask clinicians and they’d say there’s no clear evidence for this,’ says Fox. ‘It’s hard because some people say they or their child is allergic when in fact they aren’t [often misnaming a sensitivity to certain foods an allergy]. There are massive over estimates. While we don’t have the definitive evidence it looks like the trend is [over the very long term] towards a gradual increase in food allergy. Yet the prevalence is still low.’

That amounts to about five percent of children. That’s still a major public health issue – not least because an allergy can take a child from fine to unconscious at lightning speed. It’s one that should encourage governments to implement better national allergy strategies – better training in allergies for doctors, better readiness to address allergy issues in schools. But it’s nothing like an epidemic. Nothing like the 30 per cent rate that would be the case if parents were asked the question about their children. Deaths from food allergy are extremely rare – a child has a greater chance of dying in an accident. But death rates are, thankfully, stable or falling.

Causes and Contributors

Indeed, we’re not quite sure what causes allergies either. The leading hypothesis was once that regarding hygiene: that we, and children especially, lived lives that were too clean; not, as it were, playing in the dirt enough to be exposed to allergens in a way that allowed children to build tolerance. This is now widely discredited. ‘There was a lot of hysterical hype [around that theory] and the fact that it’s easy to understand made it easy to enter the public consciousness. But it’s proven very hard to get it out,’ says Fox. 

There are now investigations into whether allergies are a product of toxins or perhaps a lack of vitamin D – since children spend more time inside now. But, as Boyle points out, these lines of inquiry assume allergy rates are on the up. The leading hypotheses points towards a mix of genetic factors – asthma and eczema, for example, are 80 percent inherited – and something going on in our gut microbiomes. 

‘There’s more interest now in understanding how our gut has a huge influence on how we interact with the outside world,’ says Fox. That, he adds, has implications for weaning practises – breast-feeding boosts the infant’s microbiome; for natural birth – which gives the newborn a chance to ingest important bacteria from mum; and on our consumption of ultra-processed foods. 

No wonder parents are confused with all the mixed messaging too, though Fox boils advice down to this: don’t delay in introducing potentially allergenic foods to your child, from around four to six months old (not least because they can be exposed to some through the skin, not just through eating). Do so in small doses and – crucially – do so regularly. Don’t try some peanut, see no reaction, conclude there’s no allergy and then no longer give peanut. It doesn’t work that way. Allen calls more work to be done to help parents overcome a natural nervousness to follow this approach.

‘The fact is that we’re in the infancy of our understanding of allergies,’ says Fox. ‘Allergies are geographically very disparate but culturally very different too. These are just highly complex diseases.’

Why Misdiagnosis Matters

To say that makes studying them complex too is an understatement: there’s great variation to individual immune responses, for example, and the threshold for reaction can vary in an individual from day to day. As a 2017 study demonstrated, even when current allergy tests are positive, the person is not actually allergic half of the time. 

The skin prick test – in which the skin is scratched by a needle coated with proteins from a suspect food and any irritation examined – may still be the standard but that’s over 100 years old. What’s really required is the observation of objective symptoms during what’s called an oral food challenge – a placebo-controlled test involving ingesting the suspected allergenic and seeing what happens. But these are time consuming and difficult to use for large population studies. Some better, easier tests are in development and may be available within the next decade.

Robert Boyle concedes that his may be a cynical view but he pulls no punches when he says that allergies fall into that category of medical issues – he cites the likes of ADHD, dermatology, psychiatry – over which hangs the shadow of big business.

‘There’s only been one study that looks at changes in actual physical reactions to food over time and that suggests no obvious rate of change in allergies. So what’s going on here?’ he asks. ‘Why do we have the impression that allergies are so out of control? This is a common scenario in medicine: companies leveraging parental concern to sell products, be that auto-injectors to treat anaphylaxis, or formula milk. One of the core issues in the consideration of allergies is commercial influence. That skews what gets talked about, what gets investigated, what gets funded. But there are places where we need a red line between marketing and science.’

That, he says, would bring much more clarity to the discussion around allergies. It’s a clarity we could all do with.