Peanut allergy: can environmental exposure to traces of peanuts lead to allergy?
This research was completed on 30 June 2012
Published on 18 February 2010
Around a quarter of a million children in the UK are allergic to peanuts and the number of new cases is rising.1 We don’t know how or why peanut allergies develop and there is no proven long-term treatment, so affected children must avoid eating peanuts in any form. Researchers are investigating whether environmental exposure to traces of peanuts in house dust can lead to allergy and whether some children with an impaired skin barrier are more susceptible to this than others. They hope their work will eventually lead to ways to prevent peanut allergies.
What's the problem and who does it affect?
The number of people who are allergic to peanuts has trebled in the last 10 years.2 Around one in 50 children in the UK are currently affected3 – that’s almost 250,000 children altogether.1 Once diagnosed, the majority of children remain allergic to peanuts for the rest of their lives – only one in five grow out of their allergy.4
There is no proven long-term treatment, so affected children must avoid eating peanuts altogether – in any form, at all times. This can be difficult, as traces of peanuts are found in many different foods.
If the children do eat a food that contains even a tiny quantity of peanuts, they can experience severe symptoms, particularly breathing problems. Many children must always have emergency treatment, such as adrenaline injectors, close to hand. Adrenaline injectors are used to give life-saving injections of the hormone adrenaline.
Many children with peanut allergies feel anxious about their condition and restricted by it. Their allergy can complicate even the simplest things, like going round to a friend’s house to play or sharing a piece of birthday cake.
What is the project trying to achieve?
What causes peanut allergies?
No-one knows why some children become allergic to peanuts. Recent evidence suggests that skin contact with traces of peanuts – for example, in house dust or skin creams – might lead to the allergy. One study, for example, has shown peanut allergies are more common in children with eczema, who have previously had skin creams containing peanut oil applied to their skin.
In this project, the researchers are studying 3,250 children from the USA, Australia, Sweden and the UK who have been followed up by research groups in these countries from birth or early infancy. They are measuring the levels of peanut protein in dust samples taken from the children’s homes – from bed linen, mattresses and sofas.
The researchers aim to find out whether babies who are exposed to high levels of peanuts in house dust are more likely to develop a peanut allergy. They are also investigating whether babies who have an impaired skin barrier are especially vulnerable. This includes children with eczema and children with certain variations in a gene called filaggrin (which is linked with eczema and leads to an impaired skin barrier).
What are the researchers' credentials?
|Project Leader||Professor G Lack MA MBBCh FRCPCH|
|Location||Paediatric Allergy, Department of Asthma Allergy and Respiratory Science and Department of Public Health Sciences, King's College London School of Medicine, Guy's, King's College and St Thomas' Hospital, London|
|Grant awarded||18 November 2009|
|Start date||4 January 2010|
|End date||30 June 2012|
|Grant code||SP4529, GN1763|
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The project leader, Professor Gideon Lack, heads an internationally renowned centre that is at the forefront of research into children’s allergies. The centre comprises a dedicated team of clinicians who work closely with scientists to conduct cutting-edge research that will benefit all children with allergies. The centre has recently acquired a newly renovated laboratory.
The first clues that peanut allergy might develop via exposure of the skin to traces of peanuts emerged more than 5 years ago when Professor Lack and his team published a landmark study of over 13,000 children, which showed that the majority of children with peanut allergy had suffered severe eczema in the first 6 months of life and had been treated with creams that contained peanut oil.
Dr Helen Brough, who recently joined the team, has pioneered the use of a sophisticated method to measure peanut levels in the dust of children’s homes.
Who stands to benefit from this research and how?
Striving for ways to prevent peanut allergies
The researchers hope to boost our understanding of what causes peanut allergies. They are investigating whether environmental exposure to traces of peanuts in house dust might increase a baby’s chances of developing an allergy to peanuts, and whether babies who have an impaired skin barrier – because of eczema and variations in a gene called filaggrin – are especially vulnerable.
The researchers hope their work will eventually lead to ways to stop children from developing peanut allergies, so we can halt the rising prevalence of this worrying allergy. Currently, 4,000 people, mostly children, develop an allergy to peanuts each year in the UK.5
Preventing peanut allergies could bring significant and long-lasting benefits. It could mean children have a better quality of life, free from anxiety about whether their next meal is going to cause a life-threatening allergic reaction. It may avert hospital visits, illness or even death.
It’s also possible this research could help us develop ways to prevent other food allergies as well, such as allergies to egg, milk, sesame, almonds and walnuts.
1. House of Commons Health Committee. The Provision of Allergy Services. Sixth Report of Session 2003–04. http://www.publications.parliament.uk/pa/cm200304/cmselect/cmhealth/cmhe...
2. Grundy J, Matthews S, Bateman B, Dean T, Arshad SH. Rising prevalence of allergy to peanut in children: Data from 2 sequential cohorts. Journal of Allergy & Clinical Immunology 2002; 110(5):784-789.
3. Hourihane JO, Aiken R, Briggs R, Gudgeon LA, Grimshaw KEC, DunnGalvin A et al. The impact of government advice to pregnant mothers regarding peanut avoidance on the prevalence of peanut allergy in United Kingdom children at school entry. Journal of Allergy and Clinical Immunology 2007; 312(5):1197-1202.