A major study from researchers at the Children’s Hospital of Philadelphia has revealed a significant reduction in the number of children diagnosed with peanut allergies over the past decade

Peanut allergy is one of the most common food allergies in the UK and worldwide. Affecting approximately one in 50 children (2%) and one in 200 adults (0.5%) in the UK, around one in five children outgrow their allergy.

A new study released this week reveals that expert guidelines encouraging early peanut exposure may be having a more positive impact than we might have realised. Researchers from the Children’s Hospital of Philadelphia (CHOP) have released study findings showing that the rates of diagnosis of peanut and other IgE-mediated (anaphylactic) food allergies have declined in the US since guidelines were adopted to encourage early introduction practices. 

Early exposure 

Common IgE-mediated food allergy triggers include peanuts, milk, eggs, and shellfish. These allergies can lead to hives, swelling, itching, vomiting, difficulty breathing and in severe cases, anaphylaxis. While researchers had long speculated that food allergies could be prevented through early-life exposure, a landmark study published in 2015, the Learning Early About Peanuts Allergy (LEAP) trial, showed early exposure of peanuts for 4-to 11-month-olds with severe egg allergies or eczema reduced their peanut allergy risk by 81%. Studies since have shown that this protective effect continues past early childhood. 

In the US, guidelines were put into place in 2015 and 2017 to focus on children thought to be at higher risk of developing a food allergy. In 2021, new guidelines were introduced to support the introduction of peanut, egg, and other major food allergens to all children around 4-6 months without a history of prior reaction. 

“Everyone has been wondering whether these landmark public health interventions have had an impact on reducing rates of IgE-mediated food allergies in the United States,” said study author Stanislaw Gabryszewski, MD, PhD, an attending physician in the Division of Allergy and Immunology at CHOP. “We now have data that suggest that the effect of this landmark public health intervention is occurring.”

Researchers compared the rates of food allergy diagnosis prior to the early introduction guidelines with rates post guideline introduction and post expanded guidelines. Researchers estimate that around one in every 200 infants exposed to food allergens has been prevented from developing food allergy. The study found a significant reduction in the prevalence of peanut IgE-mediated food allergy (from 0.79% to 0.45%), as well as any IgE-mediated food allergy (1.46% to 0.93%). 

While early introduction doesn’t eliminate these food allergies, the reduction rate is promising and shows the importance of a preventive approach. Researchers hope that future studies could explore specific feeding practices to help improve understanding about the timing, frequency, and quantity of common allergen foods could help to optimise protection against food allergies. 

Guidelines in the UK

In the UK, early peanut exposure guidelines were first introduced in 2017 following LEAP study findings. Before this, guidelines had recommended the delay of introducing allergens until children were at least three years old (or older amongst those with a family history). Current NHS guidelines recommend introducing food that contains peanuts from six months old, alongside other solid foods and continuing with breastfeeding or formula, and warn that a delay in the introduction of peanuts and eggs beyond 12 months can increase children’s risk of developing an allergy to these foods. While many children outgrow their allergies to milk or eggs, for some, food allergies can be lifelong.

Prior to the introduction of new guidelines in the UK, Rising trends in food allergies: A 20-year study highlighted the rising numbers of people with food allergies. The study looked into the growing number of cases of food allergies in England between 1998-2018. The study, which looked at data from over 7.6 million patients, found sharp increases in food allergy diagnosis (with numbers almost doubling between 2008 and 2018), although research also showed challenges in accurate diagnosis. Young children (under five) were found to most commonly have food allergies (4%), with only 2.4% of school-aged children, and 0.7% of teenagers and adults having food allergies, suggesting many children outgrow allergies.

Research showed the number of new food allergy cases started to level off from 2014 onwards, which was thought to be linked to public health advice encouraging the introduction of common allergenic foods early on. 

How can I tell if my child has a food allergy?

While allergic reactions usually happen within a few minutes, sometimes they can happen over a few hours or days. Common signs of food allergies include:

  • sneezing
  • red, itchy, watery eyes
  • a runny or blocked nose
  • wheezing and coughing
  • a red, itchy rash
  • feeling sick or vomiting
  • tummy pain, diarrhoea, or constipation
  • worsening asthma or eczema symptoms

While most allergic reactions are mild, some children can experience more severe reactions: anaphylaxis or anaphylactic shock. This can cause their lips and face to swell as well as breathing problems, and needs urgent treatment.

Some children and adults may have food sensitivities or intolerences, rather than allergies. A food intolerrence can commonly cause diarrhoea, bloating, farting, and tummy pain, and ususally happens within a few hours of eating certain foods. Unlike food allergies, food intolerances are not usually serious, but can make your child feel unwell. 

What do I do if I think my child has a food allergy?

If you think your child might have an allergy, the NHS says that it’s important to speak with your GP, rather than to experiment with cutting out major food groups, as this can lead to children not getting the nutrients they need. Speaking with your doctor can help get the right diagnosis and referrals for support.

Working with a nutritional professional can be one way to help better understand the foods causing your symptoms and to adjust your diet while ensuring it remains healthy and balanced. 

As research continues to evolve, it’s heartening to see how small changes in early nutrition can make such a big difference for children’s health. With continued awareness and support for parents, the next generation could grow up with fewer restrictions, more confidence at mealtimes, and a broader appreciation for the foods that once caused so much worry. While there’s still more to learn, this study brings a sense of hope, and perhaps a little relief, to families navigating their children’s first tastes and textures.