The Allergen-eration

Photo by Pixelumina Photography on Unsplash

Written by Bryony Scutt

Allergens are on the rise and now of epidemic proportion (1). “Without significant action, environmental modelling predicts that 70 per cent of people in the UK will have an allergy by 2060” (2). 

The significant rise in allergy incidence over the past 50 years can’t be explained by genetics alone and is likely to have many factors, primarily relating to our western lifestyles. There are several hypotheses that can help explain which are discussed later in the article (3). 

What is an allergy?

Food allergies are different from an intolerance, which causes symptoms such as bloating and stomach pain, usually a few hours after eating the food (5). 

It is in fact ironic, because it is our defence mechanism which causes the dangerous symptoms problems by misidentifying the food (e.g. protein in a peanut) as a threat (5). Antibodies are released to attack the food, which causes the symptoms. In 1967, Immunoglobulin E was identified, this is an antibody responsible for most allergic reactions, people prone to allergies produce a disproportionate amount of IgE (8).

Allergies are the most common chronic disorder in children (40% of children in the UK have been diagnosed with an allergy) and they’re on the rise (4). Further to this, those with hay fever are four time more likely to suffer from other conditions, driven by allergy eg. asthma, eczema and other food allergies (4, 5). This is also more likely if a close family member suffers (5). Reactions due to food allergies can be life threatening and hospital admissions caused by food allergies have tripled over the last 20 years (2).

The top 14 food allergens

Celery, cereals containing gluten, crustaceans, eggs, fish, lupin, milk, molluscs, mustard, tree nuts, peanuts, sesame seeds, soya, and sulphur dioxide (sulphites). Tree nuts include almonds, brazil nuts, cashews, hazelnuts, macadamia, pecan, pistachios, shea nuts and walnuts.

Symptoms of food allergies

These usually appear within a few minutes of eating the food, although they can be delayed for a couple of hours/days. 

Classic symptoms include:

  • Gut reactions: abdominal pain, diarrhoea, vomiting

  • Skin reactions: itching and swelling

  • Respiratory reactions: runny nose, sneezing, wheeze, cough (5, 7)

What to do 

Call 999 if you or someone:

  • Gets a skin rash from the food 

  • It has caused wheezing 

  • There is tightness in the chest or throat 

  • Trouble breathing or talking 

  • The mouth, face, lips, tongue or throat start swelling

These are signs that you or someone could be having a serious allergic reaction and may need immediate treatment (5). Epinephrine (adrenaline) is life saving for severe reactions and antihistamines are used for mild or moderate allergic reactions (7). If there is an adrenaline autoinjector (e.g. an EpiPen), use this immediately, if you know how, and call 999 (5). 

Allergies in babies and young children

Exclusive breastfeeding or fortified infant formula is recommended for the first 6 months of a baby’s life and there are alternative formula options for those with a cow’s milk allergy. Food allergies in babies and young children can be particularly worrying, especially in new parents however when pregnant or breastfeeding there is no need to avoid the allergen foods unless you, yourself are allergic to them. There is also no evidence to delay introducing foods that can trigger allergic reactions, in fact it is positively encouraged to prevent the likelihood of developing an allergy in the future (especially peanuts and hen’s eggs). These need to be given one at a time and in very small amounts to spot any adverse reaction. If there is a family history of allergens, or your baby has an allergy e.g. eczema or another food allergy this needs to be done carefully and following the advice of your GP or health visitor (9).

For children, the most common and life-threatening allergies are peanut (2% of children in the UK), cow’s milk, and egg allergy. Having an egg allergy can include allergy to all or some forms of egg (well-cooked, loosely cooked and raw), someone with this allergy only needs to avoid the forms they react to (7).

Unfortunately research has shown that 15% of children currently visit a GP 10 times before receiving an allergen diagnosis (6). It’s important to follow up any unusual reactions with your GP to prevent any future adverse reaction. 

Allergy at school

Most school classrooms will have at least one allergic pupil and 20% of severe allergic reactions happen whilst a child is at school. Sometimes this is their first reaction with no prior history of an allergy and so there is a clear need for careful management. Instead of advocating for blanket bans on particular allergens within the school environment model policy encourages a culture of allergy awareness and education (7). 

 

Outgrowing allergies

It is possible for a child to outgrow their food allergy(s), this is for those where symptoms usually appear in the seconds or minutes after exposure to the food. This is particularly true for allergies to cow’s milk, wheat and eggs. Allergies to peanuts, tree nuts, fish and shellfish are less likely to be outgrown (10). 

Current research

The Natasha Clinical trial

In 2016 Natasha Ednan-Laperouse tragically died from eating sesame seeds that were baked into some dough on a flight, due to a legal loophole. Since, her family have paved the way to changing the laws and perception of allergens. There are ways ways to improve the lives of those living with allergies, to prevent these from becoming life threatening. Allergic children are not born with life threatening allergies, they (and an increasing number of adults) become allergic over time, so science is searching for answers. 

A ground-breaking oral immunotherapy trial has been launched which uses everyday foods taken under medical supervision to improve tolerance over time. This hopes to desensitise children to cow’s milk and peanut allergies by using them as everyday foods and is showing great promise in up to 80% of people. Over the long term, this is more cost effective than other medical drugs such as Palforzia currently available on the NHS for desensitising children to peanuts and hence will increase opportunity to treat more people in the UK (2). 

How do allergies develop?

Hygiene hypothesis 

This hypothesis evolved to consider that reduced exposure to foreign microbes (microscopic organisms) is a major factor for allergic disease incidence. This reduced exposure could be due to cleaner food and water; sanitation; use of antibiotics and vaccines; migration patterns; and delivery modes during childbirth. It is also important to consider that individuals living with allergies have less diverse gut bacteria than individuals without allergies, which could explain why the immune system is less tolerant to foreign allergens. Despite the negative effects on increasing allergen incidence, anti-infectious measures are undoubtedly important for our society. Both personal and public cleanliness and sanitation efforts are significant due to the growing threat of emerging infectious diseases (1, 3).

Climate change

Another explanation considers global warming and its impacts on weather patterns due to the accumulation of greenhouse gases. Since the 1970s, average temperatures have increased by around 1 degree Celsius, which has caused great fluctuations in regions. This is now widely appreciated to affect the development, morbidity, and mortality of allergic diseases. Mechanisms for this include modified pollination patterns and prolonged heat waves (encouraging increased time inside) (1, 3). 

During the recent global allergy symposium (conducted by the Natasha Allergy Research Foundation) it was noted that reduced biodiversity in the environment affects the body’s microorganism content and diversity of the microbiome, which increases the risk of developing allergies. It also provided a link between genes and the environment such as the role of indoor pollution on allergy incidence and how farming practices can affect people (2).

Take home messages:

  • Try not to exclude foods unnecessarily, this could mean missing out on important nutrients. 

  • Delayed introduction of foods to children is counterproductive, seek advice from your GP. 

  • It is essential to be able to recognise the signs of an allergic reaction in yourself or others and feel confident in managing it safely and effectively. 

  • If you or someone close to you has an adverse reaction to a food, make sure to follow it up and keep getting tested until there is a clear diagnosis. 

This blog post was written by Bryony Scutt, a public health nutritionist at Family Action, currently delivering the National School Breakfast Programme. Bryony graduated from University College London with a masters degree in Clinical Nutrition and Public Health and also has a bachelor’s degree in chemistry from The University of Birmingham. Bryony enjoys experimenting with new recipes, getting outside in nature, and trying out new sports. You can find Bryony on LinkedIn here.

References

1. Rothenberg ME. The climate change hypothesis for the allergy epidemic. Journal of Allergy and Clinical Immunology. 2022;149(5):1522-4.

2. Natasha Allergy Research Foundation. 

  [Available from: https://www.narf.org.uk/the-natashas-foundation-global-allergy-symposium. (Accessed: 22/06/23)

3. Platts-Mills TAE. The allergy epidemics: 1870-2010. Journal of Allergy and Clinical Immunology. 2015;136(1):3-13.

4. Natasha Allergy Research Foundation. Allergies - The Facts  [Available from: https://www.narf.org.uk/the-allergy-explosion. (Accessed: 22/06/23)

5. NHS UK. [Available from: https://www.nhs.uk/conditions/food-allergy/. (Accessed: 24/06/23)

6. AllergyUK. Food Allergy. [Available from: https://www.allergyuk.org/about-allergy/allergy-in-childhood/cows-milk-allergy/. (Accessed: 26/06/23)

7. AllergyUK. Types of allergies  [Available from: https://www.allergyuk.org/types-of-allergies/food-allergy/. (Accessed: 26/06/23)

8. National Geographic.  [Available from: https://www.nationalgeographic.com/science/article/partner-content-brief-history-of-allergies. (Accessed: 26/06/23)

9. NHS UK. [Available from: https://www.nhs.uk/conditions/baby/weaning-and-feeding/food-allergies-in-babies-and-young-children/. (Accessed: 24/06/23)

10. Anaphylaxis UK. Will a child outgrow an allergy?  [Available from: https://www.anaphylaxis.org.uk/fact-sheet/outgrowing-a-food-allergy/#:~:text=A%20recent%20study%20(2020)%20found,and%2068%25%20by%20age%2016. (Accessed: 27/06/23)


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