Food Allergies FAQ

Managing Food Allergies

What causes food allergies to specific foods has been researched for many years. When somebody has a reaction to food, that individual's immune system sees that particular food product – for example peanut – and thinks that it is something harmful for the body.

This is because people with food allergies have been exposed to that food in a way that made the immune system think that this was something harmful rather than something innocuous that wouldn't cause any problem.

When the individual then has contact with that food – say peanut – by either by eating it, some goes into their eye or if it's rubbed onto some broken skin, they could get an allergic reaction. This is because their immune system has already recognised that this is something that is foreign and needs to be dealt with.

Allergies, like most chronic conditions, are caused by a combination of genetic and environmental factors. More recently there has been a breakthrough in understanding that if a child has an inflamed disrupted skin barrier in the first year of life, and they are potentially exposed to allergenic foods through the skin, this causes the immune system to pick up on that food as something that is harmful to the body.

Going back to our previous example of peanut, the child then develops an allergic response to peanut and the next time the child is exposed to peanut the body starts to have an allergic response.

A top tip for those suffering from food allergies would be to get a proper allergy diagnosis so that they know exactly what it is that they are allergic to. For example, somebody could have a reaction to scrambled egg, and think that they're allergic to the egg, but it could be the milk that was used to prepare the scrambled egg. So, it's very important to get some proper allergy testing which can be done by skin test or a blood test using a specific IgE testing.

Once you have a formal allergy diagnosis, then you need to have a good understanding of the types of allergic reactions you might have. You could get an immediate allergy reaction which would cause hives and swelling and potentially anaphylaxis. Or it could be a delayed allergy reaction, in which case it would cause allergy symptoms later, a few hours after eating the food, and that could be skin rashes or eczema or gut issues.

You need to know how to identify the types of reactions that you're going to have and how to manage them. If you are experiencing a food allergic reaction, the first thing would be to stop eating the food that's causing the issue. You need to know how to manage the food allergy, including having a proper emergency plan, particularly for those with immediate food allergies that will need the right medication.

Then you need to ensure that you know how to avoid that food once you know what you are allergic to, such as by reading food labels properly. Telling people that you have an allergy is a good idea, so that they don't give it to you inadvertently.

It's also important to make sure that if you have a food allergy – for example to cow’s milk – and you avoid cow's milk in your diet, and that you make sure your diet has enough in the way of calcium, vitamin D and iodine. This is because you may lack those nutrients if you're not having cow's milk, so it's important to look into that to make sure that nutritionally your diet is complete. This is even more important when managing food allergies for children who are still growing and in breastfeeding mothers who have increased calcium requirements.

Whether the body can be trained in getting rid of food allergies is something that has been intensely researched in the last five to ten years. We know that with immunotherapy for inhalant allergens– for example for pollen allergies and house dust mite allergy – can have injections, take tablets or sprays under the tongue, which can help to retrain the immune system to be less allergic to those inhalant allergies.

When it comes to foods, in terms of certain foods that are naturally outgrown – for example most children outgrow their egg and milk allergy – there are things that can be done to help that individual outgrow their milk and egg allergy more quickly. This can be done by introducing baked forms of that food into the diet. Please that this does need to be done under medical supervision, rather than just at home.

There are certain food allergies that are more persistent, meaning that once a child has that allergy, usually they remain allergic for the rest of their lives. Examples include that only 20% of children outgrow their peanut allergy and only 10% of children outgrow tree nut allergies such as cashew and walnut allergy.

The question whether immunotherapy (also known as desensitisation) actually ‘gets rid’ of food allergy is really important because a lot of the media has been portraying this food allergy treatment as a cure. What the studies have shown is that it does not cure the food allergy but it does reduce the risk of accidental reactions to the food and reduces severity of allergic reaction if a reaction does occur.

The person doing the food allergy desensitisation or oral immunotherapy program needs to continue taking that food every day for the rest of their lives. This means that it's not something that would be defined as a ‘cure’. A cure would be that you no longer have to think about eating that food, you can just eat it whenever you want. Rather than a cure, we say it will make that individual ‘bite proof’. An example would be if they are peanut allergic and had some peanut by mistake in a restaurant, they would be much less likely to have an allergic reaction. Also if they were to have an allergic reaction, studies have shown that it is much more likely to be a milder allergic reaction than if they were not taking this treatment.

When it comes to food allergy reactions, you have two types of food allergy – immediate allergy reaction and delayed allergy reaction. Immediate food allergy causes hives and swelling, itchy, runny nose, vomiting, and in the most severe cases could lead to problems with the airway, breathing or consciousness.

For immediate food allergies symptoms – for example a skin rash hives, or swelling – then using a non-sedating antihistamine such as cetirizine is a good treatment. These can be bought over the counter for children over the age of two years, because it is licensed from that age. However, for children under the age of two, this would need to be prescribed.

In terms of more severe allergic symptoms such as problems with airway, breathing, or circulation, this is something that needs to be treated with adrenaline. This is also known as an anaphylactic reaction (a life-threatening allergic reaction). Adrenaline auto injectors are not available over the counter so they do need to be prescribed. This emergency medication is the gold standard treatment for anaphylaxis and if it is used you must always call 999 to get emergency services and say the word ‘anaphylaxis’.

It's so important when managing food allergies for you or your child, that you see somebody who is able to diagnose the allergy and any related allergies properly, and give you a personalised emergency plan to help you to recognise allergic symptoms and know how to manage them. Read more about how we can help with food allergy management.

When it comes to delayed allergies, the symptoms may be an eczema flare or maybe some gastrointestinal issues. For an eczema flare, many good moisturisers are available over the counter and the National Eczema Society has some great information about this. If the skin becomes very red and inflamed there are some topical steroids that can be applied. Some of these are available over the counter, and some need to be prescribed.

When it comes to the gut, and symptoms associated with the gut, it's very much about removing the offending food from the diet to see if that improves the symptoms. Sometimes some people can use a non-sedating antihistamine, like cetirizine which may help, but the main treatment would be to avoid the foods causing the symptoms.

Want to know more Allergic Rhinitis Facts? Read the full article on All you need to know about allergic rhinitis by consultant paediatric allergist Dr Helen Brough.

In the case of a food allergy in children, there are two primary types: immediate food allergies (IgE-mediated) and delayed food allergies (non-IgE-mediated). Immediate food allergies are more commonly recognised, as they manifest shortly after consuming the allergenic food, typically within one to two hours. These allergies often exhibit classic symptoms, such as:
  • Hives resembling a nettle rash
  • Swelling around the mouth or eyes, which can extend to different parts of the body
  • Vomiting or having loose stools
  • Sneezing or rubbing the nose and/or eyes
  • Rarely, anaphylaxis (problems breathing)
  • Persistent cough or swollen tongue
  • Trouble breathing or wheezing
  • Impact on blood pressure, leading to dizziness or sudden sleepiness
  • Paleness or appearing floppy
This is all mediated by a few different parts of the immune system, but mainly IgE (immunoglobulin E antibodies made by the immune system).

In the case of delayed food allergies, children do not exhibit immediate reactions to the allergenic food. Instead, they experience delayed responses that can encompass a broad spectrum of symptoms. Unlike immediate food allergies, which are mediated by IgE, delayed food allergies involve a different component of the immune system. This immune response can result in the following manifestations:
  • Itching
  • Flare-up of redness on the skin
  • Dry, itchy patches resembling eczema
  • Appearance of small dots under the skin
  • Gastrointestinal issues, particularly severe colic, stomach pains, loose stools, constipation, or gastroesophageal reflux (more common in young babies)
A classic example in babies is cow's milk proctocolitis, where the child can have bloody stools in the first few weeks of life through exposure to cow's milk.

Please note that both immediate and delayed food allergies can present with various symptoms and may differ from person to person. It's important to consult a healthcare professional for an accurate diagnosis and appropriate management of food allergies.
In the United Kingdom and many other Western countries, the prevalence of food allergies in children ranges from 6 to 8 percent. A recent study in the UK revealed a rate of 7.1 percent, with immediate food allergies accounting for approximately 2 to 3 percent, and likely a higher percentage for delayed allergies.Among the common food allergies, egg allergy is the most prevalent, affecting around 5 percent of children. Cow's milk allergy has a wide range of prevalence since it can cause both immediate and delayed reactions, but it is more commonly associated with delayed allergies.

Peanut allergy is also quite common among children, affecting approximately 2 to 2.5 percent. Additionally, there are other food allergies such as tree nut allergy, sesame seed allergy, fish allergy, wheat allergy, soya allergy, and kiwi allergy. Furthermore, rarer food allergies are emerging, including chia seed allergies and other newly introduced foods in the diet.

Children do not possess inherent food allergies or eczema at birth; these conditions develop as they grow older. However, there exists a crucial period during which preventive measures can be taken to reduce the risk of food allergies in children who develop eczema, as most food allergies tend to emerge by the age of one.It is important to note that food allergies can often manifest upon the first exposure to a particular food. For instance, in the case of peanut or egg allergies, the initial allergic reaction frequently occurs when a child consumes scrambled eggs for the first time or has a small amount of peanut butter on toast. This may puzzle people who assume that a prior ingestion should have alerted the body to the impending allergy.

However, recent discoveries have shown that individuals can develop allergies through skin contact. If a child has eczema, characterised by red, inflamed, and irritated skin, exposure to certain foods on the skin can increase their susceptibility to developing an allergy to those specific foods. Hence, food allergies can seemingly arise suddenly, but in reality, the child was already allergic—they simply had not encountered that particular food yet.

For children with a history of immediate food allergies, there is now a range of reliable tests available to determine the presence of a food allergy. Additionally, research tests are accessible to gauge the severity and threshold level of food reactions. During clinic visits, we commonly conduct an allergy-focused history assessment and perform a skin prick test.

We utilise specialised commercial extracts for various foods, and parents can also bring fresh fruits and vegetables if they have concerns about specific items. In addition to food testing, we may also include environmental allergens such as grass pollen as part of our comprehensive approach.

As previously mentioned, immediate food allergies are mediated by the antibody IgE. Fortunately, we now have advanced blood tests at our disposal that examine specific protein components within the food. These tests enable us to determine if a child is allergic to those specific protein components.

This distinction is highly valuable in differentiating between primary food allergies, which can result in severe allergic reactions, and pollen food syndrome, which typically leads to milder reactions and is associated with hay fever. These sophisticated blood tests provide crucial insights for accurate diagnosis and appropriate management of food allergies.

Diagnosing delayed food allergies can be challenging. While patch testing to food is available, the most reliable method to determine if a child is allergic to a specific food is through a meticulous exclusion of that food from the diet, with appropriate dietary substitutes to ensure proper nutrition.

This exclusion period is followed by a systematic reintroduction of the food in small amounts while closely monitoring and documenting any associated symptoms in a diary. This careful process of elimination and reintroduction allows for a more accurate assessment of the child's allergic response to food intolerance and helps in making an informed diagnosis of delayed child food allergies.

A crucial step when a child is diagnosed with an allergy is to confirm the allergy through appropriate allergy testing. It is not uncommon to encounter cases where families believed their child reacted to one food when, in fact, the reaction was triggered by something else entirely.For instance, I once had a family visit me, convinced that their child had an egg allergy. However, upon further investigation, we discovered that the child's reaction was actually due to allergies to milk used in preparing the scrambled eggs, rather than the eggs themselves.

This highlights the importance of undergoing thorough allergy testing to accurately identify the specific allergen affecting the child. Sometimes, what may appear as a food allergy may turn out to be something different altogether. Obtaining a proper diagnosis through allergy testing is the first and crucial step in managing allergies effectively.

Once a proper diagnosis is established, it is vital to receive comprehensive advice on how to avoid the allergenic food and take necessary precautions. This includes:
  • Allergen Avoidance: Understanding how to read allergy labels on packaged foods to identify potential allergens and ensure safe consumption.
  • Dealing with "May Contain" Labels: Learning how to assess and manage the risks associated with products that may contain traces of the allergenic food.
  • Eating away from home: Guidance on navigating restaurants, including communicating dietary needs to staff, asking what ingredients are in the foods when there is either a formal, buffet style or family style service, and making informed choices.
  • Handling Takeaways: Understanding how to navigate food options from takeout establishments with no food labels while ensuring allergen safety.
  • Recognising Allergic Reactions: Educating parents on identifying the signs and symptoms of an allergic reaction in their child.
  • Response to Symptoms: Providing clear instructions on how to address different types of allergic reaction symptoms after a child eats, including when and how to administer appropriate medications.
  • Emergency Action Plan: Developing a personalised emergency plan that outlines steps to be taken in case of severe allergic reactions, including the use of epinephrine auto-injectors and seeking immediate medical attention.
  • Nutritional Alternatives: Ensuring suitable substitutes and alternatives to the allergenic food are available to maintain proper nutrition and support the child's growth and development.
By providing comprehensive guidance in these areas, parents can effectively manage their child's food allergy, minimise risks, and maintain a safe and healthy lifestyle. Read more about food allergy prevention, food allergy management and food allergy desensitisation.
As part of my practice, I ensure that each of my patients with a food allergy receives a personalised emergency treatment plan. This plan addresses various scenarios based on the severity of symptoms:Mild to moderate symptoms of child food allergiesSymptoms such as rashes, swelling of the eyes or lips, vomiting, or changes in behaviour can typically be managed with an antihistamine medication.

Severe allergic reactions (Anaphylaxis)
  • In the event of a life threatening severe allergic reaction that may impact the airway, breathing, or consciousness (anaphylaxis), intramuscular adrenaline is considered the gold standard treatment.
  • Parents must first ensure their child is in the appropriate position. If the child is experiencing consciousness issues, they should lie down with their legs elevated. If the child is experiencing airway or breathing difficulties, they can sit up but should not be fully upright.
  • It is crucial to administer the adrenaline auto-injector immediately (training on proper usage is provided in my clinic). Following administration, the child should remain in the same position, and someone should call emergency services at 999, explicitly stating "anaphylaxis."
By providing clear instructions tailored to each child's specific needs, parents can effectively respond to allergic reactions, ensuring the appropriate measures are taken promptly while seeking immediate medical assistance.

I offer my patients prescriptions for emergency treatments they need. These can be used to request conversion to an NHS prescription through their general practitioner (GP). Additionally, I ensure that they receive written information on how to effectively handle their allergies, as well as details about the specific food items to which they have been confirmed allergic.

To further support them, my practice collaborates closely with dietitians who can offer additional guidance on avoiding allergenic foods, addressing any nutrient deficiencies in their diet, and providing recipes for alternative food options.

Want to know more about symptoms and diagnosing child food allergies? Read the full article on Don’t take the risk: know your child’s food allergies by consultant paediatric allergist Dr Helen Brough. Specialist in prevention, diagnosis and management of food allergies. More information can be found on our services page.


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