What are some rare food allergies
Food allergies happen when the immune system – the body’s defence against infection – mistakenly treats proteins found in food as a threat.
As a result, a number of chemicals are released. It’s these chemicals that cause the symptoms of an allergic reaction.
Almost any food can cause an allergic reaction, but there are certain foods that are responsible for most food allergies.
Foods that most commonly cause an allergic reaction are:
- tree nuts
- some fruit and vegetables
Most children that own a food allergy will own experienced eczema during infancy.
The worse the child’s eczema and the earlier it started, the more likely they are to own a food allergy.
It’s still unknown why people develop allergies to food, although they often own other allergic conditions, such as asthma, hay fever and eczema.
Read more information about the causes and risk factors for food allergies.
What is food intolerance?
A food intolerance isn’t the same as a food allergy.
People with food intolerance may own symptoms such as diarrhoea, bloating and stomach cramps. This may be caused by difficulties digesting certain substances, such as lactose. However, no allergic reaction takes place.
Important differences between a food allergy and a food intolerance include:
- you need to eat a larger quantity of food to trigger an intolerance than an allergy
- the symptoms of a food intolerance generally happen several hours after eating the food
- a food intolerance is never life threatening, unlike an allergy
Read more about food intolerance.
Sheet final reviewed: 15 April 2019
Next review due: 15 April 2022
In July 2016, Natasha Ednan-Laperouse collapsed on a flight from London to Nice, suffering a fatal allergic reaction to a baguette bought from Pret a Manger.
At an inquest, the court heard how Natasha, who was 15 and had multiple severe food allergies, had carefully checked the ingredients on the packet. Sesame seeds – which were in the bread dough, the family later found out – were not listed. “It was their fault,” her dad Nadim said in a statement. “I was stunned that a large food company love Pret could mislabel a sandwich and this could cause my daughter to die.”
This horrifying case highlights how careful people with allergies need to be, as do the food companies – not least because allergies own been growing in prevalence in the past few decades.
“Food allergy is on the rise and has been for some time,” says Holly Shaw, nurse adviser for Allergy UK, a charity that supports people with allergies.
Children are more likely to be affected – between 6 and 8% of children are thought to own food allergies, compared with less than 3% of adults – but numbers are growing in westernised countries, as well as places such as China.
“Certainly, as a charity, we’ve seen an increase in the number of calls we get, from adults and parents of children with suspected or confirmed allergy,” says Shaw. Certain types of allergy are more common in childhood, such as cow’s milk or egg allergy but, she says: “It is possible at any point in life to develop an allergy to something previously tolerated.”
Stephen Till, professor of allergy at King’s College London and a consultant allergist at Guy’s and St Thomas’ hospital believe, says that an allergic reaction occurs when your immune system inappropriately recognises something foreign as a bug, and mounts an attack against it.
“You make antibodies which stick to your immune cells,” he says, “and when you get re-exposed at a later time to the allergen, those antibodies are already there and they trigger the immune cells to react.”
Allergies can own a huge impact on quality of life, and can, in rare cases such as that of Natasha Ednan-Laperouse, be fatal. There is no cure for a food allergy, although there has been recent promising work involving the use of probiotics and drug treatments.
The first trial dedicated to treating adults with peanut allergy is just starting at Guy’s hospital.
“There is a lot of work going on in prevention to better understand the weaning process, and there’s a lot of buzz around desensitisation,” says Adam Fox, consultant paediatric allergist at Guy’s and St Thomas’ hospitals. Desensitisation is conducted by exposing the patient to minuscule, controlled amounts of the allergen.
It’s an ongoing treatment though, rather than a cure. “When they stop having it regularly, they’re allergic again, it doesn’t change the underlying process.”
What we do know is that we are more allergic than ever. “If you ponder in terms of decades, are we seeing more food allergy now than we were 20 or 30 years ago? I ponder we can confidently tell yes,” says Fox.
“If you glance at the research from the 1990s and early 2000s there is beautiful excellent data that the quantity of peanut allergy trebled in a extremely short period.”
There has also been an increase in the number of people with severe reactions showing up in hospital emergency departments. In 2015-16, 4,482 people in England were admitted to A&E for anaphylactic shock (although not every of these will own been below to food allergy).
This number has been climbing each year and it’s the same across Europe, the US and Australia, says Fox.
Why is there this rise in allergies? The truth is, nobody knows. Fox doesn’t believe it is below to better diagnosis. And it won’t be below to one single thing.
There own been suggestions that it could be caused by reasons ranging from a lack of vitamin D to gut health and pollution. Weaning practices could also influence food allergy, he says. “If you introduce something much earlier into the diet, then you’re less likely to become allergic to it,” he says. A 2008 study found that the prevalence of peanut allergy in Jewish children in the UK, where the advice had been to avoid peanuts, was 10 times higher than that of children in Israel, where rates are low – there, babies are often given peanut snacks.
Should parents wean their babies earlier, and introduce foods such as peanuts?
Fox says it’s a “minefield”, but he advises sticking to the Department of Health and World Health Organization’s line that promotes exclusive breastfeeding for six months before introducing other foods, “and to not delay the introduction of allergenic foods such as peanut and egg beyond that, as this may increase the risk of allergy, particularly in kids with eczema”. (Fox says there is a direct relationship between a baby having eczema and the chances of them having a food allergy.)
The adults Till sees are those whose allergies started in childhood (people are more likely to grow out of milk or egg allergies, than peanut allergies, for instance) or those with allergy that started in adolescence or adulthood.
Again, it is not clear why you can tolerate something every your life and then develop an allergy to it. It could be to do with our changing diets in recent decades.
“The commonest new onset severe food allergy I see is to shellfish, and particularly prawns,” says Till. “It’s my own observation that the types of food we eat has changed fairly a lot in recent decades as a result of changes in the food industry and supply chain.” He says we are now eating foods such as tiger prawns that we probably didn’t eat so often in the past.
He has started to see people with an allergy to lupin flour, which comes from a legume in the same family as peanuts, which is more commonly used in continental Europe but has been increasingly used in the UK.
Sesame – thought to own been the cause of Natasha Ednan-Laperouse’s reaction – is another growing allergen, thanks to its inclusion in products that are now mainstream, such as hummus. One problem with sesame, says Till, is: “It often doesn’t show up extremely well in our tests, so it can be hard to gauge just how allergic someone is to it.”
Fox says it’s significant to stress that deaths from food allergy are still rare. “Food allergy is not the leading cause of death of people with food allergies – it’s still a extremely remote risk,” says Fox. “But of course you don’t desire to be that one who is incredibly unlucky, so it causes grand anxiety.
The genuine challenge of managing kids with food allergy is it’s really hard to predict which of the children are going to own the bad reactions, so everybody has to act as if they might be that one.”
To prevent a reaction, it is extremely significant to avoid every fish and fish products. Always read food labels and enquire questions about ingredients before eating a food that you own not prepared yourself.
Steer clear of seafood restaurants, where there is a high risk of food cross-contact. You should also avoid touching fish and going to fish markets. Being in any area where fish are being cooked can put you at risk, as fish protein could be in the steam.
More than half of people who are allergic to one type of fish are also allergic to other fish.
Your allergist will generally recommend you avoid every fish. If you are allergic to a specific type of fish but desire to eat other fish, talk to your doctor about further allergy testing.
Fish is one of the eight major allergens that must be listed on packaged foods sold in the U.S., as required by federal law. Read more about food labels
There are more than 20,000 species of fish. Although this is not a finish list, allergic reactions own been commonly reported to:
- Mahi mahi
Also avoid these fish products:
- Fish oil
- Fish gelatin, made from the skin and bones of fish
- Fish sticks (some people make the error of thinking these don’t contain genuine fish)
Some Unexpected Sources of Fish
- Imitation or artificial fish or shellfish (e.g., surimi, also known as “sea legs” or “sea sticks”)
- Barbecue sauce
- Caesar salad and Caesar dressing
- Worcestershire sauce
- Caponata, a Sicilian eggplant relish
- Certain cuisines (especially African, Chinese, Indonesian, Thai and Vietnamese)—even if you order a fish-free dish, there is high risk of cross-contact
Allergens are not always present in these food and products, but fish can appear in surprising places.
Again, read food labels and enquire questions if you’re ever unsure about an item’s ingredients.
What is a Food Allergy? There Are Diverse Types of Allergic Reactions to Foods
Most food allergies affect younger children under the age of 3.
Most children who own food allergies to milk, eggs, soya and wheat in early life will grow out of it by the time they start school.
Peanut and tree nut allergies are generally more endless lasting.
Food allergies that develop during adulthood, or persist into adulthood, are likely to be lifelong allergies.
For reasons that are unclear, rates of food allergies own risen sharply in the final 20 years.
However, deaths from anaphylaxis-related food reactions are now rare.
Types of food allergies
Food allergies are divided into 3 types, depending on symptoms and when they occur.
- IgE-mediated food allergy – the most common type, triggered by the immune system producing an antibody called immunoglobulin E (IgE).
Symptoms occur a few seconds or minutes after eating. There’s a greater risk of anaphylaxis with this type of allergy.
- non-IgE-mediated food allergy – these allergic reactions aren’t caused by immunoglobulin E, but by other cells in the immune system. This type of allergy is often hard to diagnose as symptoms take much longer to develop (up to several hours).
- mixed IgE and non-IgE-mediated food allergies – some people may experience symptoms from both types.
Read more information about the symptoms of a food allergy.
Oral allergy syndrome (pollen-food syndrome)
Some people experience itchiness in their mouth and throat, sometimes with mild swelling, immediately after eating unused fruit or vegetables.
This is known as oral allergy syndrome.
Oral allergy syndrome is caused by allergy antibodies mistaking certain proteins in unused fruits, nuts or vegetables for pollen.
Oral allergy syndrome generally doesn’t cause severe symptoms, and it’s possible to deactivate the allergens by thoroughly cooking any fruit and vegetables.
The Allergy UK website has more information.
When to seek medical advice
If you ponder you or your kid may own a food allergy, it’s extremely significant to enquire for a professional diagnosis from your GP. They can then refer you to an allergy clinic if appropriate.
Many parents mistakenly assume their child has a food allergy when their symptoms are actually caused by a completely different condition.
Commercial allergy testing kits are available, but using them isn’t recommended.
Numerous kits are based on unsound scientific principles. Even if they are dependable, you should own the results looked at by a health professional.
Read more about diagnosing food allergies.
In the most serious cases, a person has a severe allergic reaction (anaphylaxis), which can be life threatening.
Call 999 if you ponder someone has the symptoms of anaphylaxis, such as:
- breathing difficulties
- trouble swallowing or speaking
- feeling dizzy or faint
Ask for an ambulance and tell the operator you ponder the person is having a severe allergic reaction.
The best way to prevent an allergic reaction is to identify the food that causes the allergy and avoid it.
Research is currently looking at ways to desensitise some food allergens, such as peanuts and milk, but this is not an established treatment in the NHS.
Read more about identifying foods that cause allergies (allergens).
Avoid making any radical changes, such as cutting out dairy products, to your or your child’s diet without first talking to your GP.
For some foods, such as milk, you may need to speak to a dietitian before making any changes.
Antihistamines can assist relieve the symptoms of a mild or moderate allergic reaction. A higher dose of antihistamine is often needed to control acute allergic symptoms.
Adrenaline is an effective treatment for more severe allergic symptoms, such as anaphylaxis.
People with a food allergy are often given a device known as an auto-injector pen, which contains doses of adrenaline that can be used in emergencies.
Read more about the treatment of food allergies.