Anaphylaxis is a frightening event. It can come on suddenly and progress rapidly, requiring immediate medical treatment. After the initial episode, the patient must be vigilant at all times in order to avoid their allergy trigger – whether it is a food, an insect sting, latex, a prescribed drug or any other agent.
The Anaphylaxis Campaign
The Anaphylaxis Campaign is a national registered charity, now celebrating its 25th year. Its overall aim is to protect people at risk from this unpredictable condition.
I co-founded the charity in January 1994 after my 17-year-old daughter Sarah, who was a trainee hairdresser, died from an overwhelming allergic reaction to peanut.
Her death occurred after she ate a dessert in a town centre restaurant in Guildford, Surrey. She suffered from chronic asthma and had an inkling that she was allergic to peanuts, but had no idea how serious her allergy could be. On that fateful day in October 1993, the dessert caused her throat to swell and close up, she suffered a severe asthma attack and her blood pressure plummeted. Unknown to her, the dessert contained peanut.
Before the 1990s, food allergy was generally regarded by people as a minor inconvenience. It was out there on the fringes of medicine. At most it was considered that food allergy amounted to no more than a touch of indigestion or an itchy rash. Some cases were thought to be ‘all in the mind’. That changed at the end of 1993 when the UK media reported that four people had died suddenly in a short space of time from allergic reactions to nuts, including my daughter Sarah.
The resulting media publicity spread alarm throughout the food industry and placed immense pressure on the Government to take action. For if people's lives were at risk from a common, everyday food that was nutritious for the majority, what were the implications for food production and labelling?
As a result of those four tragic deaths, and others that came to light, the Anaphylaxis Campaign was formed with me as its co-founder and chairman. A small core group of a dozen of us (people with food allergy and the parents of children with food allergy) met in a flat near Baker Street, central London, in January 1994. We had never met before, but made contact as a result of the huge wave of media coverage that occurred. That informal London get-together was the inaugural meeting of the Anaphylaxis Campaign, which began its life as a small pressure group run out of people's homes. Our objective was to save lives, and in those early months we set out to be a focal point for the spread of information.
This proved to be more straightforward than we had dared to hope. After the Campaign's launch, and the resulting media publicity, I received 60–70 letters a day, many of them told heart-rending stories of children who had been rushed to casualty suffering from extreme allergic reactions to food.
Along with the information provided to us by health professionals, the influx of case histories from people with allergies provided a comprehensive file from which to develop guidance for patients and the industry alike. We met the Parliamentary Secretary at the Ministry of Agriculture, Fisheries and Food, Nicholas Soames, in February of 1994; some of the major retailers and manufacturers in March; and the Department of Health in April.
Prevalence of allergy
Today the importance of allergy is well recognised. The World Allergy Organisation (WAO) estimate allergy prevalence to range between 10–40% of the population (Pawankar et al, 2013).
More than 150 million Europeans suffer from chronic allergic diseases, and it is predicted that by 2025 half of the entire EU population will be affected (European Academy of Allergy and Clinical Immunology, 2016).
From 1992–2012 there was a 615% increase in the rate of hospital admissions for anaphylaxis in the UK (Turner et al, 2015).
Anaphylaxis during general anaesthesia occurs in 1 in 10 000–20 000 anaesthetics. These patients may be denied general anaesthesia in the future unless a safe combination of drugs can be identified (National Institute for Health and Care Excellence (NICE), 2014).
Food allergy
For 25 years, the Anaphylaxis Campaign has remained in the forefront of efforts to raise the level of debate, working with patients, health professionals, educators and the food industry.
Today, a clinical panel of 20 medical experts, including prominent UK allergy specialists, guide the organisation to ensure our approaches are sensible and evidence-based. All our patient information materials carry the quality mark of the Information Standard, a certification scheme for health and social care information, established by the Department of Health to help the public make informed choices about their lifestyle, their condition, and their options for treatment and care.
These materials cover a wide range of allergens. While peanut allergy has attracted most media coverage, many other triggers of anaphylaxis exist and these are often overlooked. There are 14 foods subject to mandatory allergen labelling, including eggs, milk, soya, shellfish, fish, and even lupin – one of those obscure foods that is now known to trigger reactions. And, of course, there are non-food causes of anaphylaxis – including certain drugs, insect venom and latex.
However, it is food allergy that accounts for at least 90% of our work. An average of 10 people die each year in the UK as a result of food-induced anaphylaxis and many other incidents involve ‘near misses’ – where the allergic individual has been revived thanks to emergency treatment. Although these figures are low compared with deaths from other causes, the level of anxiety is often high. To the outsider, the fear expressed by families who care for a food-allergic child can appear out of all proportion. The level of apprehension becomes understandable when you realise that there is a frightening unpredictability to severe food allergy. Many of those affected have experienced sudden life-threatening episodes requiring an emergency dash to hospital.
Fortunately, there is plenty that patients can do to lower the risk to themselves and to be prepared to treat a reaction should it occur. This is something that health professionals can make clear to patients.
Pre-loaded adrenaline auto-injectors (AAIs) are available on prescription for people thought to be at risk of anaphylaxis. In our view, the patient (or the patient's parents, in the case of a child) should be helped to write a care plan to help them recognise when an allergic reaction has started, and how to treat it. If the patient has asthma as well as allergies, it should be well controlled. There is strong evidence to suggest that poorly-controlled asthma will raise the chances of any allergic reaction being severe (Pumphrey and Gowland, 2007).
‘Anaphylaxis during general anaesthesia occurs in 1 in 10 000–20 000 anaesthetics’
The number of AAIs that should be prescribed for each patient has been the subject of much discussion. In 2014, the UK's Medicines and Healthcare products Regulatory Agency (MHRA) advised that anyone who is at risk of suffering anaphylaxis should always have at least two AAIs immediately available. The MHRA (2014: 28) report said:
‘It is acknowledged that in some cases, a single injection is not sufficient to achieve a response for a number of reasons, including severity of attack as well as the possibility that a dose has not been effectively administered; a second injection may therefore be needed.’
The Anaphylaxis Campaign supports this view.
In cases where the risk of anaphylaxis is thought to be low, there is a difference of opinion among health professionals. While some allergy specialists agree that two AAIs must always be immediately available (in line with the MHRA report), others believe it is sufficient to have one device available, arguing that one injection is likely to be enough to treat the symptoms until emergency medical help arrives. This should be considered in the light of the patient's individual history and the likelihood of a life-threatening reaction.
Health professionals need to make a judgement on whether a referral is required. Many cases of allergy can be dealt with in primary care. But in more difficult and complex cases – particularly where anaphylaxis is a possibility – a referral to an NHS allergy clinic is important.
Vaccine allergy
Our helpline receives frequent calls from patients seeking information on which vaccines are safe for people with food allergies. Fortunately, there has been plenty of research on this subject.
MMR
The MMR vaccine is normally cultured on cells from chick embryos. However, it is generally regarded to be safe for children with egg allergy.
In 2010, an article published in Clinical and Experimental Allergy said (Clark et al, 2010: 1123):
‘All children with egg allergy should receive their normal childhood immunisations, including the MMR vaccination, as a routine procedure performed by their family doctor/nurse…Studies on large numbers of egg-allergic children show there is no increased risk of severe allergic reactions to the vaccines. Children who have had documented anaphylaxis to the vaccine itself should be assessed by an allergist.’
Flu
The flu vaccine is prepared on hen's eggs and may contain tiny amounts of egg protein, but research suggests that flu vaccines present a very low risk of anaphylaxis for people with egg allergy even when the allergy is severe (Greenhawt et al, 2012). However, we believe that people who have suffered severe reactions to egg should have their case assessed by an allergy specialist before having the flu vaccine. This also applies to anyone with egg allergy whose asthma is difficult to control. It may be decided that the benefits of being vaccinated outweigh the risk of a reaction. In these cases, either a ‘no-egg’ or ‘low-egg’ vaccine can be given and this is usually tolerated.
Recently, a flu vaccine was introduced for children that is not injected, but sprayed into the nose (Live attenuated influenza vaccine – LAIV). This is the recommended vaccine for the childhood flu programme. While this vaccine contains minute quantities of egg protein, research has shown that it can be safely administered to children with egg allergy (Turner et al, 2015). Public Health England (2015) has advised that children with a history of severe anaphylaxis to egg who has required intensive care should be referred to specialists for immunisation in hospital. Egg-allergic children with asthma can receive LAIV if their asthma is well-controlled.
Yellow fever
The yellow fever vaccine is also grown on egg and has higher potential to cause an allergic reaction. It is possible to desensitise patients and successfully complete immunisation, but this should only be carried out in specialist centres (Rutkowski et al, 2013).
Drug allergy
A small, but significant, number of calls to our helpline come from people worried about allergic reactions to prescribed medicines.
One study conducted in two large hospitals in Merseyside found that adverse drug reactions accounted for approximately 6.5% of hospital admissions (Pirmohamed et al, 2004), although not all of these were allergic in nature. Other reactions are idiosyncratic, pseudo-allergic or caused by drug intolerance. The British Society for Allergy and Clinical Immunology (BSACI) defines drug allergy as an adverse drug reaction with an established immunological mechanism (NICE, 2014).
‘The British Society for Allergy and Clinical Immunology (BSACI) defines drug allergy as an adverse drug reaction with an established immunological mechanism’
According to NICE, about half a million people admitted to NHS hospitals each year have a diagnostic ‘label’ of drug allergy, with the most common being penicillin allergy. About 10% of the general population claim to have a penicillin allergy; often due to a skin rash that occurred during a course of penicillin in childhood. However, the figure is thought to be significantly lower. Fewer than 10% of people who think they are allergic to penicillin are truly allergic (NICE, 2014). Therefore, penicillin allergy can potentially be excluded in 9% of the population. Studies have shown that people with a label of penicillin allergy are more likely to be treated with broad spectrum, non-penicillin antibiotics (NICE, 2014). However, use of these antibiotics in people with an unsubstantiated label of penicillin allergy may lead to antibiotic resistance (NICE, 2014).
Helpline
Recently our helpline received the following queries:
Question: ‘My doctor suspects I have severe penicillin allergy and has referred me to an allergy specialist for testing. What tests are likely to be carried out?’
Our answer: ‘To refute or confirm penicillin allergy, you may be offered skin testing, followed by an oral challenge if the skin test is negative. Blood testing for penicillin allergy is very inaccurate. History taking can be helpful, but even with a very strong history of penicillin-associated anaphylaxis, many individuals will be negative to penicillin allergy testing, particularly if the reaction occurred more than 10 years ago.’
Question: ‘I experienced dizziness and lightheadedness while receiving a local anaesthetic at the dentist. What should I do?’
Our answer: ‘Local anaesthetic allergy is quite rare. Patients may experience symptoms related to anxiety surrounding procedures requiring the use of local anaesthetics. In our view, you should seek a referral to an allergy clinic for a proper evaluation. Skin testing and a challenge may be carried out so that you can undergo future procedures comfortably with a local anaesthetic.’
Support
The Anaphylaxis Campaign has programmes of support and education for people affected by life-threatening allergies, and for schools and employers. We continue to inform and encourage the food industry, which faces significant challenges in ensuring that food is safe and properly labelled for people with allergies. What food companies require is information and guidance based on high-quality evidence. In March 2003, we set up a membership scheme for the industry in which we offer our subscribers newsletters and the opportunity to attend seminars where problems can be discussed and analysed. Around 120 companies, including major retailers and manufacturers, are now members of this scheme.
Regulations
We concluded early on in the Campaign's history that patients really need the knowledge that the food industry operates consistent, high-quality standards for the control of food allergens.
In 2014, EU regulations came into force, tightening up the rules governing the labelling of pre-packed food. As stated earlier, any of 14 key allergens must be included in the ingredient list and emphasised – for example, in bold, italic or coloured type.
The regulations also cover food sold in catering establishments, including restaurants, cafés, takeaways, pubs, hotels, burger vans, schools, hospital cafeterias and anywhere else where catered food is served. Such food businesses are required to provide information to customers about the presence of any of the 14 major allergens. This information can be provided in writing or by word of mouth. If information is provided by word of mouth, the food business must ensure written signage is clearly visible to tell customers that allergen information is available from the staff. Systems must be in place to ensure that, if requested, the information given is supported in a recorded form to ensure accuracy.
Precautionary allergen labelling
With regard to pre-packed products, the message for people with food allergies is clear: always read the label carefully. But there is a complication. In the early 1990s, retailers and manufacturers began to add warning labels to products advising customers that a product ‘may contain’ a particular allergen, such as nuts. This practice – known in the food industry as Precautionary Allergen Labelling – soon spread like wildfire, to the annoyance and frustration of people with food allergies. The fact that these warning labels appeared to turn up randomly – even on bottled water or bags of lettuce – led people to the conclusion that there was no genuine risk and food producers were simply covering their backs.
We believe these warnings are often there for a good reason. The risks of cross-contamination during the production chain can be very real. A person with allergies may eat a product numerous times without having a reaction, but the next time they may not be so lucky. Cross-contamination can be intermittent.
What does the future hold?
What people really want is a ‘cure’. Can the effects of a severe allergic reaction be reduced by drugs, and can allergy even be switched off altogether?
Oral immunotherapy (OIT) may provide some optimism. It works by slowly introducing small amounts of the allergen into the patient's diet at regular intervals and gradually building up to larger amounts over time. It is hoped that eventually the immune system adapts to tolerate the food. Successful immunotherapy helps to protect allergic individuals against reactions following accidental exposure. Research teams have achieved promising results in various countries including the UK, the US and Germany.
The Addenbrooke's group at Cambridge demonstrated that peanut immunotherapy was successful in the majority of peanut-allergic children who took part in a clinical trial, including some with a history of anaphylaxis (Anagnostou et al, 2011).
There are now a number of sites taking part in commercially-sponsored OIT studies in the UK. In London, NHS research into both peanut and milk allergy is taking place.
Work on OIT shows a great deal of promise, but there are still questions to be answered before the safety of the therapy can be demonstrated beyond doubt. For example, will the treatment lead to long-term tolerance? Must the children continue to eat the allergenic food long-term to maintain the protective effect? If so, how much should they eat and how often? Assuming this research continues to be successful, it will still be some time before OIT can be widely introduced.
The treatment must be conducted by medical experts in a clinical setting as the treatment is associated with a risk of reaction. Don't try this at home!