All over the world, particularly in developed nations, children are more likely to develop allergies than ever before.
Although most reactions are mild, the fact they can be fatal means patients and families have to live in fear and be constantly vigilant when purchasing food products in supermarkets and restaurants – but why are food allergies more common now?
What Is an Allergic Reaction?
An allergy is a reaction our body has to substances called allergens when they come into contact with our skin, nose, eyes, respiratory tract or gastrointestinal tract.
If you've ever experienced sudden, unexplained bouts of sneezing, a blocked nose, a red and itchy rash, or wheezing and coughing, it's likely you've had some form of allergic reaction.
There's a good chance you have, since allergies are genuinely common – the Asthma and Allergy Foundation of America estimates that over 50 million Americans have experienced various types of allergies. Allergies are particularly common in children, and while some resolve with age, many persist for life. Adults can also develop new allergies to things they weren't previously sensitive to.
Most allergic reactions are mild and manageable with medication, while severe reactions can be life-threatening.
What Are the Most Common Causes of Allergic Reactions?
Our immune system produces antibodies to protect us from foreign substances and viruses. In someone with an allergy, though, the immune system mistakenly produces antibodies against something that isn't actually harmful, treating it as a threat.
People can be allergic to almost anything, but some substances are far more likely to trigger a reaction, including:
- Grass and tree pollen (commonly known as hay fever)
- Certain foods, particularly nuts, fruit, shellfish, eggs and dairy products
- Certain medicines, including ibuprofen, aspirin and some antibiotics
- Mould
- Household chemicals, such as those found in some detergents and hair dyes
- Dust mites
- Animal dander – tiny flecks of skin
Unlike food intolerance symptoms, which can take hours to appear after eating the trigger food, allergic reactions usually happen within minutes of exposure.
The most common symptoms include:
- Sneezing
- A blocked or runny nose
- Red, itchy and watery eyes
- Wheezing and coughing
- A red, itchy rash
- Worsened asthma or eczema symptoms
The most dangerous allergic reaction is anaphylaxis, which requires immediate medical attention.
Why Food Allergies Are More Common
According to the U.S. Centers for Disease Control and Prevention, the number of children with food allergies increased by approximately 50% between 1997 and 2011. This trend has also been observed in other developed nations, with around 7% of children in the UK and 9% in Australia affected by food allergies.
There are several theories proposed to explain this increase.
Are We Just More Aware of Allergies?
It's worth asking whether we're simply seeing higher diagnosis rates because of greater awareness.
Allergy experts generally dismiss this as the main explanation, though self-reporting does introduce some noise into the data – as many as three to four times more people believe they have a food allergy than actually do, often due to confusion between allergies and food intolerance.
That said, data from multiple studies shows a genuine, significant global increase in allergies, rising from around 3% of the population in 1960 to approximately 7% by 2018.
The "Hygiene Hypothesis"
This isn't about keeping our homes too clean – it's the idea that from a young age, our gut isn't encountering enough diverse microorganisms.
Modern homes, for example, are built with biocide-treated timber and plasterboard, and the microbiota – the organisms within our living environments – are now quite different from the environments humans evolved alongside. Encountering fewer of these microbes early in life may leave the immune system less prepared to respond appropriately to foreign substances. This is supported by research showing that children who receive more antibiotics are more likely to develop a food allergy.
Dual-Allergen Exposure Theory
Back in the 1990s, when food allergy rates first began rising noticeably, parents were commonly advised to delay giving allergenic foods to children until age three. This guidance wasn't evidence-based, and current understanding suggests it may have actually worked against what parents should have been doing.
A baby not eating a particular food doesn't mean they aren't being exposed to it in other ways. If an infant's first exposure to something like peanuts happens through inhaling dust particles, or via broken skin from eczema or a rash, their immune system may become sensitised to it – meaning the first time they actually eat it, their body reacts as though it's a threat.
Current guidance generally supports introducing allergenic foods early, rather than avoiding them – this is particularly relevant for children with eczema, since broken skin makes it easier for allergenic proteins to enter the body this way.
Vitamin D Deficiency
Research has also identified a link between sunlight exposure and food allergy risk.
Research conducted in Australia found that children with vitamin D deficiency were three times more likely to develop an egg allergy, and eleven times more likely to develop a peanut allergy.
Vitamin D plays a role in regulating immune function, which may help reduce allergic sensitivity. However, modern lifestyles – more time spent indoors, alongside sensible sun protection advice for children – have contributed to rising rates of vitamin D deficiency more broadly.
Getting Your Allergies Tested
Do you frequently experience uncomfortable symptoms after eating but aren't sure which part of your diet is causing it? Our allergy tests are designed to uncover how your body reacts to a range of food and drink items, so you know exactly what to avoid.
With easy-to-follow instructions and simple return packaging to our lab, finding out whether you have a food allergy has never been more straightforward.
