Almost 1 in 12 young children suffer from a food allergy and they seem to be getting more and more common – but what are food allergies, would you be able to recognise if your child had one and what could you do about it?
What is a Food Allergy?
The last 40 years has seen a dramatic rise in allergic diseases such as asthma, eczema and hay fever, particularly in the Western world. Along with this ‘allergy epidemic’ has come an increase in food allergies. Once a medical curiosity, almost every class room in the US, UK and Australia now has a child who has to avoid milk, egg, or nuts. Food allergies occur when your immune system becomes confused – instead of ignoring harmless food proteins, it triggers a reaction, which leads to the release of a chemical called histamine. It is histamine which causes the classic allergy symptoms of hives or swelling. More severe reactions are called anaphylaxis, and this may be life threatening. Scientists are still puzzled as to why there has been such a rapid increase in allergies. The most popular explanation is the ‘Hygiene Hypothesis’ which suggests that the increasing cleanliness of the modern world is leaving our immune systems under-stimulated. With too few bacteria and viruses to fight, our body’s defences start to direct inappropriate responses against harmless things such as pollen or foods. Indeed, as parts of the developing world are becoming more westernised, an increase in allergies is being noticed by doctors.
Most serious food allergies start in infancy and early childhood. They are caused by a relatively small number of different foods. Milk and egg allergy are the most common and tend to disappear during childhood. The other common food ‘allergens’ vary depending on where you live. Whilst peanut and tree nut allergies are common in the US, UK and Australia, fish and seafood allergies are more common in South East Asia and Southern Europe. Wheat, soy, sesame and kiwi are other common problem foods.
Food Allergies in Different Parts of the World
- Worldwide – milk, egg
- USA, UK, Australia – peanut and tree nuts
- France – mustard seed
- Italy, Spain – peach, apple, shellfish
- Israel – sesame
- Spain, Japan – fish
- Japan – buckwheat
- Singapore – birds’ nest, shellfish
How will I Know if My Baby has a Food Allergy?
Food allergies are much more common amongst children who come from families where other members suffer from allergy. Babies who suffer from eczema are particularly at risk of having food allergies. The more severe the eczema and the earlier in life that it began, the more likely there is to be a food allergy. A baby with severe eczema before 3 months of age is very likely to suffer from food allergies.
Some food allergies are quite easy to spot – as soon as the food is eaten (often for the first or second time), an itchy rash develops, usually around the mouth. There may also be swelling of the face, runny nose and itchiness as well as vomiting. In severe reactions, there may be difficulty breathing and if this occurs an ambulance should be called immediately. Fortunately, severe reactions are very rare in young children and tend to be more of a problem amongst teenagers.
Symptoms of an immediate food allergy:
Mild to moderate symptoms typically affect the skin, the respiratory system and the gut.
- A flushed face, hives, a red and itchy rash around the mouth, tongue or eyes. This can spread across the entire body.
- Mild swelling, particularly of the lips, eyes and face.
- A runny or blocked nose, sneezing and watering eyes.
- Nausea and vomiting, tummy cramps and diarrhoea.
- A scratchy or itchy mouth and throat.
Severe symptoms (anaphylaxis). These require urgent medical attention.
- Wheezing or chest tightness, similar to a severe asthma attack.
- Swelling of the tongue and throat, restricting the airways. This can cause noisy breathing (especially on breathing in), a cough or a change in voice
- A sudden drop in blood pressure (called hypotension) leading to shock.
- Dizziness, confusion, collapse, loss of consciousness and sometimes coma.
Sometimes, food allergies can be more subtle and difficult to detect, especially if they are delayed allergies. These allergies tend to be more of a problem in infancy. In the past, these allergies were sometimes called food intolerance, but this isn’t the correct term because, strictly speaking, an intolerance does not involve the immune system. Delayed allergic reactions do involve the immune system, but unlike the histamine release characteristic of an immediate reaction, delayed allergies involve parts of the immune system that take much longer to respond. The end result means it’s difficult to pinpoint a particular food as the problem and sufferers may continue to eat and drink it.
Delayed allergies in infants may cause chronic symptoms such as eczema, reflux, colic, poor growth, diarrhoea or even constipation. The symptoms only get better when the food is removed from the diet, with milk, soy, egg, and wheat being the most common culprits. However, all of these symptoms commonly occur during childhood and an allergy is only one possible explanation, not the only one. Trying to work out whether the underlying problem is due to a food allergy can be very difficult and requires the help of an experienced doctor.
In 2011, NICE (National Institute of Clinical Excellence) issued guidelines to GPs on how to assess and diagnose children with suspected food allergy. If you feel that your concerns are not being taken seriously by your doctor then it would be worth consulting the parents’ guide to these recommendations (www.nice.org.uk).
Symptoms of delayed food allergy
- Eczema
- Reflux – an effortless vomiting
- Poor growth
- Swelling in the small bowel
- Constipation and/or diarrhoea
- Raising knees to chest with tummy pain
- Frequent distress and crying
What Should I do if I Suspect an Allergy?
Immediate allergies to food are usually quite easy to spot because of how quickly they happen after the food is eaten. If you think that your child has had an immediate reaction, it is best to avoid the food until you have seen a doctor. If you suspect that something in your child’s diet is causing more delayed symptoms such as eczema or reflux then it can be helpful to keep a food diary to see if the relationship between having the food in the diet (or your diet if you are breast feeding) and the symptoms is consistent. If it is, then the diary will be helpful to the doctor who you take your child to see.
What Can My Doctor do for Me?
Diagnosing food allergies relies on a careful medical history, examination and special allergy tests. Your doctor will ask you about the symptoms of the reaction, whether they have happened every time the food has been eaten, and how long they took to appear. With immediate type allergies, testing can be done by a blood test or by a ‘skin prick’ test, where food extracts are placed on the skin of the arm and gently pricked. The results of either test can be very helpful in confirming if the allergy is present. Unfortunately, with delayed allergies, things are less straightforward as there are not any reliable straightforward tests. However, careful exclusion diets, where the suspected food is completely taken out of the diet may be recommended with the assistance of an experienced dietician. If the food is the cause of the symptoms then they should improve when the food is withdrawn. This exclusion period should be followed by reintroduction of the food to ensure than any improvement really was due to the food being removed. If the symptoms are relieved on exclusion and return on reintroduction then a diagnosis can be reached.
Looking After a Child with a Food Allergy
The best treatment for a food allergy is to completely avoid the problem food. Being diagnosed with a food allergy has a massive impact on the whole family. Eating is such a central part of day to day life that having to be absolutely sure that a child has no contact with a particular food affects mealtimes, going to school, holidays and social occasions. A simple supermarket trip has been shown to be almost 40% longer when shopping for a food allergic child. Parents also need to be able to recognise reactions and know exactly how to deal with them when they occur. This usually involves carrying anti-histamines everywhere the child goes and also, for those children at risk of anaphylaxis, adrenaline injections. Children with food allergies are also at risk of missing out of the essential nutrients that they would otherwise get from the food they are avoiding, especially in the case of infants with milk allergy. Fortunately, there are now many specially designed milk substitutes suitable for these children and, with the help of a dietician, a nutritious diet can be achieved even in children with multiple food allergies.
Many food allergies, such as egg and milk, are outgrown during childhood whilst allergies to peanuts, nuts, fish and shellfish tend not to go away. Children with food allergies also have a high chance of having other allergic problems such as asthma, eczema and hay fever.
It is essential that children with food allergies continue to be seen by their doctors as they grow up. Repeating allergy tests can help predict if the allergy has been outgrown so that the food can be carefully reintroduced into the diet. It is also essential that the child is carefully examined for any signs that they are missing out on any essential nutrients due to their restricted diet, or if they are developing signs of other allergic problems.
Unfortunately, there are no straightforward cures for food allergy in the immediate future although exciting research, particularly in the area of desensitisation, does promise real progress over the next few years, not only in our understanding of how to prevent allergies occurring in the first place but also for helping those who already have them.
Dieticians can help parents to make sure that a child with a food allergy has a varied and nourishing diet, and this ensures healthy growth and development. It can also play an essential part of minimising the impact on your lifestyle by offering acceptable foods.
Treatment
Sometimes foods such as hypo-allergenic milk, or other suitable foodstuffs, may be prescribed, or it may be that medication is needed and you may be prescribed anti-histamines, adrenaline injector devices, or inhalers. Adrenaline treatment in the form of an adrenaline injector is sometimes needed when food allergies can trigger the serious reactions, as mentioned above.
Food allergy can potentially have the greatest impact upon the lifestyle and choices made by a child and their family. However, with clear understanding of the issues, and through having good routines in place to cover both food choices and emergency situations, the impact of food allergy can be kept to a manageable level.
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