Here are some useful facts and figures on the prevalence of allergies and anaphylaxis:How common is allergy and anaphylaxis?
- In the UK, 1-2% of adults have a food allergy. This, combined with the 5-8% of children with a food allergy, equates to about 2 million people. This figure doesn’t include those with food intolerances. This means the actual number of affected people living with food allergy and/or food intolerance is considerably more. (Food Standards Agency 2016)
- The United Kingdom has one of the highest incidences of allergy in the world (Nwaru, Hickstein et al. 2014)
- Up to 11% , or 7 million people, have allergies severe enough to require specialist allergy care (BSACI 2011)
- 13 million people below the mid-forties have 2 or more allergies (Allergy The Unmet Need, 2003)
- An estimated 21.3 million adults (33%) in the UK suffer from at least one allergy (Mintel, 2010)
- An estimated 10 million adults suffer from more than one allergy (Mintel, 2010)
- Over 150 million people have allergies in Europe, the most common chronic disease (EAACI, 2014)
- Allergy is a chronic disease that is expected to affect more than 50% of all Europeans by 2025 (EAACI, 2015)
- Allergic diseases are affecting the lives of more than one billion people worldwide. With an epidemic rise during the last 60 years, their prevalence is expected to reach up to 4 billion in 2050s
Children and allergies:
- 10% of children and adults under the age of 45 have 2 or more allergies (Allergy The Unmet Need, 2003)
- The rate of hospital admissions for allergies for both genders is highest in those aged 0-4, and it is higher in males than in females this age group (HSCIC, 2014)
- 33% of adolescents prescribed adrenaline do not carry it with them (Youth Survey, Anaphylaxis Campaign)
- There has been an increase in hospital admissions for allergic reactions and anaphylactic shock in England. Data shows that there were 5497 hospital admissions in 2018-19 for anaphylactic shock. This compares to 4479 admissions in 2015-16 . Data shows that there were 33,904 hospital admissions in 2018-19 for allergies. This compares to 25,167 admissions in 2015-16. (NHS Digital)
- UK hospital admissions for food allergies have increased by 500% since 1990 (Gupta, 2007)
- Hospital admissions from all-cause anaphylaxis increased by 615% from 1992 to 2012 (Turner, 2015)
- Around 62,000 people every year are put in hospital because of an adverse reaction to a drug (NICE, Hospital Episode Statistics from 1996 to 2000 reported that drug allergies and adverse drug reactions accounted for approximately 62,000 hospital admissions in England each year) (NICE, 2014)
- 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. (NICE, 2014)
- £900million per annum spent by Primary Care is due to allergy (Enquiry Into Provision of Allergy Services, 2004)
- £68million per annum is the cost of hospital admissions due to allergy (Enquiry Into Provision of Allergy Services, 2004)
Psychological Impact of Anaphylaxis:
- Parents of children with a food allergy reported higher stress, anxiety, and depression compared to parents of children with no food allergy. (Birdi, G., R. Cooke and R. Knibb 2016)
- Up to 1 in 5 allergic people live in fear of death from a possible anaphylactic shock or asthma attack (EAACI, 2015)
- 41% of parents indicated an increase in stress levels since the diagnosis of their child. Activities such as family social events and parties are often affected and many parents try to minimise the anxiety caused by such activities by avoiding them (Bollinger, 2006)
Anaphylaxis is the most severe form of allergic reaction and can be life threatening. The whole body is affected, often within minutes, but sometimes within hours, of exposure to a substance which causes an allergic reaction (allergen).
Any allergic reaction, including the most extreme form, anaphylaxis, occurs because the body’s immune system reacts inappropriately in response to the presence of a substance that it wrongly perceives as a threat.
An anaphylactic reaction is caused by the sudden release of chemical substances, including histamine, from cells in the blood and tissues where they are stored. The release is triggered by the reaction between the allergic antibody (IgE) and the substance (allergen) causing the anaphylactic reaction. This mechanism is so sensitive that minute quantities of the allergen can cause a reaction. The released chemicals act on blood vessels to cause the swelling in the mouth and anywhere on the skin. There is a fall in blood pressure and, in asthmatics; the effect is mainly on the lungs.
Look for any of the following symptoms following exposure to an allergen:
- Generalised flushing of the skin
- Nettle rash (hives) anywhere on the body
- Swelling of throat and mouth
- Difficulty in swallowing or speaking
- Alterations in heart rate
- Severe asthma
- Abdominal pain, nausea and vomiting
- Sudden feeling of weakness (drop in blood pressure)
- A sense of impending doom or helplessness
- Collapse and unconsciousness
A patient would not necessarily experience all of these symptoms.
Anaphylaxis is treated with injectable adrenaline prescribed in the form of an adrenaline auto-injector. Find out more about the adrenaline auto-injector devices available for prescription in the UK here.
Adrenaline acts quickly to open up the airways, reduce their swelling and raise the blood pressure. To work effectively, it must be given as soon as possible if there are any signs of a severe allergic reaction. With early treatment those more severe symptoms are easier to reverse.
The adrenaline injectors prescribed in the UK at present are EpiPen®, Jext® and Emerade®. They are designed for self-use and that is why they are usually referred to as ‘adrenaline auto-injectors’ or ‘AAIs’.
If a patient has suffered a significant allergic reaction in the past – whatever the cause – then any future reaction is also likely to be severe. If a significant reaction to a tiny dose occurs, or a reaction has occurred on skin contact, this might also be a sign that a larger dose may trigger a severe reaction. It is particularly important that those with asthma as well as allergies are seen by an allergy specialist, as asthma can put a patient in a higher risk category. Where foods such as nuts, seeds, shellfish and fish are concerned, even mild symptoms should not be ignored because future reactions may be severe.
Allergies can develop in anyone at any time, but certain groups are more at risk, for example those who have relatives with allergies and so are genetically predisposed to develop them. If neither parent has an allergy the chance of a child being allergic is only 5 – 15 per cent and if one parent is allergic about 25 per cent. However, if both parents are allergic 50 – 70 per cent of the children are likely to have allergies. It is the tendency that is passed down – not an allergy to a specific food or substance.
Children and babies are also more likely than older individuals to develop allergies.
You can find out more about the causes of allergy and anaphylaxis here.
Although often confused, food allergy and food intolerance are mediated by different biological systems. Intolerances have a wider range of symptoms than allergy.
Someone with food intolerance may suffer migraine and unexplained fatigue (central nervous system), abdominal pain, bloating and frequent diarrhoea (gastrointestinal system), unexplained muscle and joint pains (musculoskeletal system) and unexplained nasal congestion and discharge (upper respiratory system). In the case of food allergy the symptoms are more likely to be a swelling of the tissues (e.g. in the face or throat), a skin rash or hives, asthma, or – in extreme causes – a fall in blood pressure. These symptoms are also more likely to be immediate in their onset.
Find out more about food intolerance here.
There are currently no known cures for allergies or anaphylaxis, however, there are several management approaches that allergic individuals can adopt to live a normal life and avoid reactions. Avoidance techniques should be practiced and include identifying your allergen(s) through specialist testing and excluding these from your diet and/or contact in daily life. This could include actions, such as reading labels on food and personal care products, or reducing exposure to insects for venom allergies.
Controlled Oral Immunotherapy (OIT) clinical trials have and are taking place across the globe. OIT works by slowly introducing small amounts of the problem allergen into the allergic 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 USA and Germany.
The Addenbrooke’s group at Cambridge, UK, showed 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. U.S. research led by Dr Wesley Burks and Dr Robert Wood has also achieved success with peanut, milk and egg. Studies have also taken place with milk in Leicester, UK.
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.
There is no single cause for the rising prevalence of allergy that has taken place over the past few decades. There are numerous possible reasons for this and many are still under debate. Understanding the allergy epidemic is a work in progress, but here are some factors that have been considered influential:
- Eating habits
- Early exposure to allergens
- Modern medicines, e.g. antibiotics
- Vitamin D deficiency and other dietary factors