From the Summer 2003-2004 issue of Allergy Today. For more articles like this, subscribe to Allergy Today, click here.

Peanut allergy is one of the most common food allergies, and one of the most dangerous. Unfortunately many people still don’t take it seriously, but Inga Stünzner shows you why you shouldn’t be nonchalant about this potentially life-threatening affliction.

Peanut: tale of a dangerous legume

My foray into peanut allergy began at a family gathering at my sister-in-law’s one Sunday in September last year. My daughter Stella, 13 months old at the time, was playing with her cousin and they were taking it in turns to carry a peanut butter jar. After a few minutes, we noticed the bottom half of Stella’s face had broken out in hives, and not long after one of her eyes had puffed up. A little later she began coughing. I am now appalled at my ignorance because, despite the very obvious and dangerous signs, it didn’t even register that this was an allergic reaction. I thought it was some kind of sensitivity – okay, a bit more severe – as she often broke out in a red rash when eating tomatoes. It was only when I was having a weekly phone call to my sister in Australia, who told me to go to the doctor immediately, that the seriousness started to sink in. Our family doctor didn’t mess around – he prescribed adrenaline, referred us to an allergy specialist, and my husband and I have been coming to grips with Stella’s peanut allergy ever since.

On the increase?

Everyone seems to know someone who has a peanut allergy. Since Stella was diagnosed, we have since discovered two of her cousins have a peanut allergy, as well as friends of friends. Is it our imagination, or is peanut allergy on the increase?
According to statistics, it’s not in our minds. The actual cause of this increase is unknown, although there’s a plethora of theories. One of the most popular is the hygiene theory, which makes a connection between standard of living and allergy; apparently the better our homes and living standards are, the more allergies we have. There is a definite relationship between low levels of exposure to infectious disease in babies and young children and an increased prevalence of allergies. The immune system doesn’t have enough to do in the hygienic environments we have created, so it begins to react to the allergens it comes in contact with first and most often. For an infant, this is typically a reaction to food either in the form of infant formula or the introduction of first foods too early.

Allergy specialist Dr Crump, who runs the Auckland Allergy Clinic, points out that our diets have also changed dramatically over the last 50 years. “We are eating more complex foods than our predecessors and there has been a higher consumption of peanuts, especially with vegetarian diets — and there’s the popularity of peanut butter.” The preparation may also have some influence on sensitisation (the process of initial contact with an allergen and then becoming allergic to it), as dry-roasted peanuts are more allergenic than boiled or fried peanuts. In China, for example, peanuts tend to be boiled and there are fewer cases of peanut allergy than in the Western world.

Peanut allergy had been linked to mothers eating peanuts during pregnancy and breastfeeding, however this is still controversial. And a recent study suggests there could be a link between peanut allergy and the use of arachis oil (peanut oil) in topical creams used to treat children with eczema or breastfeeding mothers with sore nipples.

“With sensitisation, you only need tiny amounts of peanut to develop an allergy,” Dr Crump says. “It could also be that the route through which peanut enters the body might affect a person’s potential to become allergic. For example, if it’s applied to the skin through a cream, or inhaled, it could be more sensitising than if it’s ingested.”

New research also suggests that while too much exposure to peanut can cause sensitisation, complete abstinence and then a small amount of exposure could be just as bad — if not worse. At the moment, the exact amount of exposure and the timing of the exposure that causes sensitisation is not known, but it would almost certainly be influenced by a person’s genetic make-up.

What’s the worry?

Peanut allergy is one of the most common food allergies and one of the most potentially fatal. In the US, it’s believed to be the leading cause of severe or life-threatening food-induced anaphylaxis, causing an estimated 15,000 emergency room visits each year and nearly 100 deaths. Most of those deaths are either teenagers or young adults. In New Zealand, it’s estimated this allergy affects 40,000 people — based on Australian statistics where 1.9 per cent of the population has a peanut allergy.

“There is little research in New Zealand into allergies and it’s badly needed,” Dr Crump says. “The UK, Canada and US have a lot of research, but New Zealand has a shortage of allergy specialists (only six in the entire country) and a shortage of funding for research.”

Because there is no hard and fast data on the prevalence of peanut allergy in this country, there are no recorded deaths. In Australia, peanut allergy is reportedly responsible for three to four deaths a year, and in the UK where there are 20 fatal reactions to food allergens a year, seven are due to peanut.

Dr Crump says the reason for the disparity between the US and the UK and Australia could be that the rate is underestimated in the latter two countries. People with fatal asthma also have a high incidence of food allergies, and a food allergy reaction could have just respiratory symptoms, resulting in the cause of death in being recorded as asthma. “It’s one area that needs collaboration between allergy and chest experts, and all people with serious asthma should have a skin prick test.”

In a study published in the Archives of Disease in Childhood in 2002, researchers from Newcastle General Hospital calculated that if 5 per cent of children in the UK have a food allergy, the risk of that child dying from it would be one in 800,000. They examined the national death statistics for children up to 15 years old, over an eight-year period, and found there were eight deaths. None of these deaths were from peanut, and no child under 13 had died from peanut allergy. There were also six near deaths in that time, but none were caused by peanut, and of 49 severe reactions, peanut was responsible for only 10.

The researchers had hoped to reassure parents worried that rates of fatal reactions were increasing dramatically, however the study instead sparked controversy. David Reading of the Anaphylaxis Campaign, UK, says what is particularly worrying is that the study may lead to some doctors becoming reluctant to prescribe EpiPens (auto-injectors of adrenaline) to children who genuinely need them. He quotes a medical advisor’s car seatbelt analogy: “You’ll probably never need it, but it’s there in case you do.”

Critics of this report believe the figures are misleading because the criteria were too narrow. Dr Crump points out that a study in Ontario, Canada, found that most food-related anaphylaxis deaths occurred amongst the 15 to 25 year-old age group— an age group excluded from the British survey. The Canadian study also found that 11 of 32 food-related deaths occurred in children, and 10 of these were caused by peanuts/nuts. Since Ontario’s 0-15 population is less than a fifth of the population size sampled in the British study, this does suggest that the number of deaths caused by food allergy in the UK may be under reported.

Meanwhile, Allergy New Zealand and its medical panel are planning to gather statistics on peanut allergy and will be setting up a register in the near future. There are also moves to begin collecting data on hospitalisations.

Who’s most at risk of a fatal reaction

The majority of people who die from peanut allergy are asthmatic: those with mild but uncontrolled asthma, and those with severe but controlled asthma who only need a small amount of exposure to peanut to cause a reaction.

“The worst case scenario is where patients don’t have a reliever because their asthma is mild, and they then have a reaction to peanut,” Dr Crump says. It’s because of this that he urges anyone with peanut allergy and asthma to have this assessed and controlled.

The second group who are most at risk of a fatal reaction are adolescents and young adults. One study analysed 32 cases of fatal food allergy-induced anaphylaxis to discover the circumstances under which the reactions occurred. They found the majority of individuals were adolescents or young adults — only three were under the age of 10 — and almost all the patients had asthma in addition to their food allergy. And peanuts and tree nuts accounted for over 90 per cent of these deaths.
It concluded that improved education of medical professionals, allergic individuals, and the public, including training in the proper use of adrenaline in food anaphylaxis, would be necessary to stop these tragic deaths.

Why are teens most at risk?

Dr Crump believes the reason teens account for the majority of deaths is because they are at an age when they are being exposed to different foods, going out and having parties, and not wanting to be labelled as being different from their peers.

The frightening fact that drugs and alcohol are easily accessible to adolescents compounds the problem. “Anything that will impair your ability to be rational will affect your judgement,” he says. “You have to act quickly and give adrenaline as soon as possible; and this is another possible reason for dying: people don’t get adrenaline quickly enough.” Alcohol could also increase the absorption of the allergen and exacerbate the reaction.

A report by the Food Allergy and Anaphylaxis Network of the USA (FAAN) into why teens are at highest risk concluded that they are reluctant to use medication, and half of those surveyed said they had been harassed about their allergies. Just under half said their allergies curtailed their social activities up to half the time.

The case of the rogue antibody

What makes peanut allergy so serious is that it is the allergen responsible for most cases of anaphylaxis, which involves the entire body and can cause it to “shut down”. People who are deemed at risk of anaphylaxis should be prescribed an EpiPen, an easy-to-use adrenaline auto-injector, which must be carried with them at all times.

What happens during an allergic reaction is the immune system mistakes a harmless substance for a dangerous one. After the first exposure to an allergen (sensitisation) the body produces specific antibodies to that allergen, called Immunoglobulin E, or “IgE”. When the person is next exposed to the allergen, such as peanut, the peanut protein locks onto the IgE, which is attached to mast cells. These mast cells are found in large numbers in the eyes, nose, lungs, intestines, and immediately beneath the skin. They contain many powerful chemicals, including a substance called histamine, which is released into the body and causes the allergy symptoms, such as runny nose, sneezing, watery eyes, itching, hives, swelling, vomiting, diarrhoea, stomach cramps and wheezing, or even anaphylaxis. This can happen within minutes or up to two hours after the food is eaten. IgE is normally produced in response to exposure to specific parasitic infections that do not occur very often in western countries.

Dr Crump says the most common manifestation of a peanut allergy is eczema or hives. “Most times, this won’t progress to anaphylaxis, but the risk should still be assessed.”
An allergy specialist will take a detailed and thorough history of the person’s allergic reactions and symptoms. They usually carry out a skin prick test and/or a blood test, known as a RAST test, which measures the level of IgE antibodies in the blood. The higher the RAST and the more dramatic the skin test response, the more likely there is a true allergy. A high test result does not, however, always predict the severity of the reaction. (See sidebar “Testing for allergy”.)

All peanut allergies are serious

“Reactions are very unpredictable,” Dr Crump cautions. “For example, if you just have a tingling of the mouth, it’s not to say you won’t have an anaphylactic reaction the next time. It could be that you didn’t have enough of the allergen to set you off. Others can have their reaction set off by exercise an hour after ingestion.” The rule, therefore, is that you should treat all peanut allergies as being serious.

This is highlighted by the tragic death of a 15-year-old Australian schoolboy four years ago. Johnny Whitburn had a peanut allergy that was not described as life threatening, as the worst symptom was a flare up of his eczema, which would have him scratching for days. He was also a mild asthmatic. Johnny was on work experience and instead of eating from his lunchbox he bought fried rice because the men he was working with were also buying their lunch. The woman who served him thought his fried rice would be bland, and added a peanut-based sauce to it. According to his mother, Cheryl, Johnny probably thought he would just scratch that night and things would be all right tomorrow. But there was no tomorrow.

Within an hour, he couldn’t breathe properly and although he tried to use his asthma spray, it was too late. Johnny was put on life support for three days, but he had been starved of oxygen for 10 to 15 minutes and was brain dead. Cheryl said they had never been told that the risk of an anaphylactic reaction existed. “When I spoke to one of Johnny’s doctors and asked him why he didn’t tell us about an anaphylactic reaction, he said because Johnny was only a mild asthmatic he thought there was no problem,” she wrote to Allergy Today at the time. The hospital Johnny was taken to is now using his story as a test case to make doctors and parents more aware of the dangers associated with peanut allergy.

How much is too much?

The type of reaction you have is generally linked to the amount of peanut needed to bring out an allergic reaction, although there are other factors that can influence whether you have a severe or milder reaction. In a study of 26 peanut-allergic people, with an average age of 25, those who had severe symptoms had a lower threshold than those who had milder symptoms.

Half the patients who reported a reaction after eating the equivalent of 1/50 of a peanut had a lower threshold than the patients who experienced mild symptoms. The threshold doses for reactions reported by the patients in this particular group were between 100 micrograms (about 1/1500 of a peanut) up to 1 gram (about 6 1/2 peanuts) of peanut protein. Threshold doses that caused observed symptoms occurred after patients ingested between 10 and 30 milligrams. No patient in this group reacted to the lowest dose of 30 micrograms. The findings of this study also highlight the importance of peanut content being labelled accurately on consumer products.

It’s important to note that these figures are based on one study only and the lowest threshold dose causing reactions has not yet been established. There is important work currently being carried out in this area, but it’s still incomplete. To get a better understanding of these thresholds in order to protect those at risk of reactions, Allergy New Zealand is following the science and participating in meetings with experts from the food industry, medicine and regulatory bodies.

Treatment

There has been a lot of research into treating peanut allergy, such as the trials of “anti-IgE” drugs like Xolair and TNX-901. These "Anti-IgE" drugs bind the IgE in the bloodstream, blocking the allergic response. TNX-901 showed great promise according to a study published earlier this year. Unfortunately, the study was stalled due to corporate squabbling between three different companies over the development rights of the drug, and it looks as though it won’t go ahead.

The only treatment at the moment is total avoidance of food containing peanuts, and for those deemed most at risk to be prescribed an EpiPen. Because some people can react to as little as 1/1500 of a peanut, it’s not a matter of avoiding just peanuts and peanut butter, but even the most minute traces of the food.

The psychological impact

Living with peanut allergy has a huge impact on the person with the allergy and their family. A study presented to an American Academy of Allergy and Immunology Symposium earlier this year found healthcare professionals often come across extreme manifestations of anxiety in families and parents.

The researchers interviewed 17 parents of children with peanut allergy and discovered if anxiety levels fall too low, the level of vigilance tends to drop. On the other hand, when anxiety is extremely high, family members experienced a disabling level of stress and fear. The study has borrowed the term “Goldilocks principle” to describe an optimal level of anxiety that is “just right”.

Allergy New Zealand’s president Natalie Lloyd says her family is typical of this syndrome. Her eight-year-old son, James, has now outgrown his peanut and milk allergies but remains allergic to egg.

“Over the years we have come to realise that every time James has had a reaction it has been after a reasonably lengthy gap since the last reaction and we have become a little complacent. It is always a huge wake-up call and brings us back to the level of vigilance that is required to keep him safe”.

The latest study on the impact of peanut allergy has found that children living with peanut allergy have a worse quality of life than those with insulin dependent diabetes. The study carried out by the University of Southampton found that young people with peanut allergy felt more threatened by potential hazards within their environment, more restricted in regard to physical activities, and more worried about being away from home than young people with insulin dependent diabetes. Two of the children even said they were scared of dying when they knew peanuts were nearby.

Dr Natalie Avery, who undertook the study, suggests improved education and better access to support services would help these children develop a more positive attitude and lower their levels of anxiety so they could live a less restricted lifestyle.

These findings are not new; although this is the first time a study has looked at the anxiety levels of children rather than parents. A study carried out in the US by FAAN last year looked at the impact of food allergy in general. It found that food-allergic families believe their child’s general health is reduced compared to most other children, and that food allergies limited family activities. The level of emotional stress of parents was also higher than in other families with conditions such as asthma and epilepsy.

Onwards and upwards

Knowing that other people face the same fears is very reassuring. This past year has been a huge learning curve for our family, especially as my husband and I have had no previous experience with allergies. I know some people consider us neurotic when we take Stella’s own food to outings, or refuse to let her have food that’s offered if we can’t read the labels. What is heartening is that although peanut allergies are notorious for causing anaphylaxis, you can minimise the risk if you’re prepared, have a management plan and take your medication everywhere with you. Now all we have to do is get our anxiety levels “just right”.

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First steps

You’ve broken out in hives, your skin’s flushed, eyes are swollen, nose is stuffy and you’re going to vomit — all of these are symptoms of an allergy. You could also have eczema, difficulty in breathing or wheezing or swelling around the mouth and nose and these symptoms occur whenever you eat or touch something with peanuts.

If you or your child has these symptoms, seek urgent medical attention at your nearest A&E clinic or call the emergency services on 111. If you or your child has previously had a reaction that you suspect could have something to do with peanuts, see your GP. Peanut allergy is the most common food allergy and the most potentially fatal. An experienced GP or allergy specialist will take a history of your reactions, examine you and arrange for skin prick tests or RAST tests. You should also be assessed for risk of anaphylaxis and prescribed adrenaline if this is the case.

Anaphylaxis is an allergic reaction that can cause severe breathing problems — wheezing, noising breathing, difficulty in breathing, swelling affecting the mouth and throat — and can also affect the cardiovascular system with low blood pressure, resulting in collapse. Death may occur within minutes.

The Australasian Society of Clinical Immunology (ASCIA) has developed an easy-to-follow action plan, outlining what to do during a mild to moderate allergic reaction through to an anaphylactic reaction. (You can download it from www.allergy.org.au/aer/infobulletins/posters/Anaphylaxis_plan_(gen)_NZ.pdf.)

If you have a mild to moderate allergic reaction, symptoms may include swelling of the lips, face or eyes, breaking out in hives or welts and abdominal pain or vomiting. Call for help, make sure someone stays with you, take medication if it’s been prescribed (usually an antihistamine), locate your EpiPen®, watch for signs of anaphylaxis and get someone to call your family or carer. If the allergic reaction progresses to anaphylaxis (breathing problems and swelling as described above), use the EpiPen® and call 111 for an ambulance. If in doubt, use the EpiPen®.

Testing for peanut allergy

Skin prick tests involve small drops of the peanut allergen being placed onto your arm or back. The skin is pricked to allow the entry of a tiny amount of allergen and if you are allergic to peanuts, a welt will appear. A blood test, also known as a Cap-RAST test, measures the level of specific IgE antibodies to peanuts and is graded between 0 and 100KU(A)L. (This measurement if for peanut allergens only, and different measures are used for other allergens.)

A positive skin test and/or RAST doesn’t automatically mean there will be a reaction to peanuts, but the larger the positive skin test or the higher the RAST test value, the more likely it is there will be a reaction if peanut is consumed.

It is impossible to predict the severity of the reaction by either the size of a positive skin prick test or the level of IgE antibody, so it’s important to practice strict avoidance and to have a management plan in place for any reactions. It is also important that your test results are interpreted by a medical professional whom has experience in diagnosing and managing food allergies.

You may also be tested for an allergy to other nuts as there is around a 20% chance of those with peanut allergy also having an allergy to a tree nut(s). In young children the recommendation may be to avoid these without testing in order to prevent allergies to them from developing.

Anyone prescribed adrenaline should invest in a Medic Alert bracelet, particularly once you’re school age or older. This will have your number, an emergency telephone number and your medical condition. In an emergency, if you can’t communicate, the bracelet will alert ambulance and medical personnel to your allergy.

Dr Crump suggests children up to the age of five who have anaphylaxis should be reassessed six-monthly to annually, depending on the number and severity of their allergies.

“Adolescents, who are at the highest risk of dying from food anaphylaxis, should be re-assessed at least annually,” he says. “The frequency of follow-ups for adults will depend on the individual. Is he or she a poorly controlled asthmatic? What is their risk of another life-threatening reaction? How allergy-aware are they?”

Getting to the right people

It’s best to see an allergy specialist, but considering there are only eight throughout New Zealand, this can be very difficult. If you go through the public system, there can be a nine-month waiting list. The other alternative is to find a GP who is knowledgeable about allergies. Ask around or call an Allergy New Zealand support person in your area.

Having a peanut allergy is an expensive business because EpiPens cost around $120 (it’s advised you have two), you’ll also need antihistamine medication and if you go privately, specialist fees aren’t cheap. There is help available through WINZ. A child disability allowance of $75.50 a fortnight is available for carers of children with a severe allergy or severe asthma. This is not income tested, but it must be verified by your child’s GP or specialist.

The Ministry of Health also has a subsidy designed to give a break to unpaid, full-time carers of a person with a disability. This may apply to parents with babies or small children with allergic conditions. It’s flexible and can be paid to friends, some family members of neighbours who provide relief care. (For further information and an application, call the Ministry of Health free phone 0800 281 22 and press 1. If you would like more information on other benefits available, contact Allergy New Zealand.

 Avoiding all traces

The only treatment for peanut allergy is total avoidance — and this is not just a matter of avoiding whole peanuts and peanut butter. You will need to learn to read food labels, and even avoid food featuring a warning statement such as “may contain traces of peanut”.

Worryingly, some people choose to ignore these warnings, believing that this is just a way of manufacturers making sure they are not held liable, or that blanket warnings are used on all products. However, there have been documented reactions, and even fatalities as a result of consuming products containing peanut that was not an intended ingredient. Many manufacturers are using these warning statements to indicate a significant risk of peanut traces being present in the product. Even though good manufacturing practices and allergen management practices may be in place, shared equipment or other uncontrolled factors, such as cross-contamination in the supply chain, may mean that while the product has not had peanut added as an ingredient, it may well pose a risk. Allergy New Zealand’s advice is to heed these warnings at all times and to contact manufacturers for more information about specific products. You must also read every label, every time. If a product has no label, don’t buy it and don’t assume that because something has been safe when you have bought it previously, that it will always be that way. Manufacturing practices, ingredients, recipes and formulations do change.

Outgrowing

Unlike other food allergies, which 80 per cent of sufferers will outgrow, peanut allergy is for life for most. Only 20 per cent of people manage to outgrow their peanut allergy.
There are several factors that make it less likely a peanut allergy will be outgrown:

• The more severe the allergy, the less likely it is to be outgrown
• If you have peanut allergy with specific peanut-IgE (RAST) level greater than 10kU(A)/L/ (it ranges from 0 to 100)
• If you have more than one allergic disorder, for example, a peanut allergy as well as eczema, asthma or hay fever
• If you are asthmatic

What you can do to protect yourself

• be on guard for unsuspected ingredients
• always be prepared to handle an allergic reaction
• recognise early symptoms
• carry a current EpiPen at all times (if prescribed)
• wear a MedicAlert emblem
• teach others how they can help
• ensure friends, family, school and daycare staff and work colleagues are fully aware of your allergy
• get to an emergency facility at the earliest signs of a reaction.
Living with a peanut allergy is not a death sentence if you follow the above steps, but don’t fall into a false sense of security and treat your allergy as unimportant.

Sources:

Journal of Allergy and Clinical Immunology, Vol. 110, No. 6.

Journal of Allergy & Clinical Immunology, Vol. 105, No. 1, S189 

Journal of Allergy and Clinical Immunology, Vol. 100, No 4 

(1)Journal of Allergy and Clinical Immunology Jan 2001

Food Allergy News, Vol. 9, No. 4

Food Allergy News, Vol. 9, No. 5.

Curr Opin Allergy Clin Immunol. 2002;2:227-231

www.foodallergy.org

www.allergy.org.nz

www.facts.com.au

Medical Reviewer: Dr Jan Sinclair

Published in the Summer 2003/2004 issue of Allergy Today.