Peanut allergies are the most common cause of death from food allergies. According to Allergy UK, incidence of peanut allergy has increased dramatically in the last 20 years to affect around 1 in 50 children today.
‘Referrals because of a peanut allergy started to rocket after about 1996,’ explains Dr Andrew Clark, consultant paediatric allergist at Cambridge University Hospital.
‘This was on the back of a big increase in the number of all allergic conditions including asthma, eczema and hay fever.’
Unlike other childhood allergies, such as cow’s milk allergy and eczema, only one in five children will outgrow their peanut allergy.
‘Fear of accidental exposure can have a big impact on quality of life and severely limit the social lives of peanut allergy sufferers and their families,’ says Dr Clark.
New hope of a ‘cure’
But a new treatment developed by Dr Clark and his Cambridge colleagues has given sufferers new hope of a ‘cure’.
The treatment uses immunotherapy – exposing allergic children to minute quantities of peanut protein. The children, aged 7 to 16, ate yoghurt containing the peanut protein in hospital and then carried on eating it every day at home for two weeks before returning to eat another with double the amount of peanut protein in.
The research, just published in the Lancet medical journal, found 84 and 91% of children in the two groups were able to tolerate 800mg of peanuts a day, after six months - which is the equivalent to five peanuts.
Dr Clark said: ‘I hesitate to use the word ‘cure’ because in order to keep up their tolerance to peanuts children would still have to eat five peanuts every day for two years after their six months of treatment, but this research is highly significant and a real game changer in how we will treat food allergies in the future.
‘This was the first trial which used immunotherapy on highly allergic children. In the past this was thought to be too dangerous – but previous studies had used injections of peanut protein in solution. We found that eating the peanuts was safer because the protein was broken down and digested rather than passing directly into the bloodstream.’
Is immunotherapy safe?
Of the 99 children in the Cambridge study, only one had a reaction so severe he needed adrenaline; most experienced itching and redness around the mouth and one in five experienced wheezing, but this could be controlled with asthma inhalers.
‘Obviously this isn’t something you should try at home – it has to be done in a hospital setting where back-up medical care and expertise is available should the child suffer an anaphylactic reaction.
‘This research was done on children but peanut allergy behaves similarly in children and adults so we believe this approach could work in adults too.’
Why is a nut allergy so dangerous?
An allergic reaction is caused when the body’s immune system mistakes a harmless substance such as nuts or other foods as harmful and produces antibodies to fight it. This results in the release of histamine which can cause itching, rashes, swelling and stomach symptoms including vomiting and diarrhoea. In a minority of cases nut allergies can result in life-threatening anaphylaxis. This is a very severe form of allergy in which the lips, face or tongue can swell up or the throat may constrict, causing breathing difficulties and even death.
Patients who have an anaphylactic reaction need to be injected with adrenaline immediately, so all nut allergy suffers should carry two EpiPens of adrenaline with them and call 999 if they feel a reaction developing.
If you have a suspected peanut allergy you should be referred to a consultant allergy specialist to have this confirmed with allergy testing.
Why are peanut allergies becoming so common?
No-one knows for sure. One popular theory is the hygiene hypothesis – that we’ve all become too clean and children aren’t being exposed to enough bacteria during a crucial window when their immune systems are developing either in the womb or early infanthood.
Living with a peanut allergy
The Anaphylaxis Campaign charity gives the following advice for avoiding peanuts and tree nuts when out and about.
- Check food labels: Under European law major food allergens must be listed in prepared foods. These include peanuts and common tree nuts (including almonds, hazelnuts, walnuts, cashews, pecan, Brazil and pistachio). If the label says “may contain nuts” this means there may be a risk of cross contamination during the production process.
- Be careful when eating out: Foods that can be problematic because they may contain nuts include satay sauces, pesto, marzipan, praline and salad dressings, as well as curries and Eastern dishes, cakes, cereal bars, biscuits and ice cream. Always ask staff if a dish contains nuts – if they are unsure then best avoid eating them.
- Always carry your medication with you: You should teach yourself how to use your EpiPen and carry them with you at all times. If your child has a nut allergy and is going somewhere without you, make sure you give the EpiPen to an adult carer and check they know how to use it.
How can I get immunotherapy for peanut allergy?
‘We hope to be opening a clinic offering a range of treatments at Addenbrooke’s in 2014 and want to see immunotherapy made available at peanut allergy clinics all over the country, both in the NHS and private sector,’ says Dr Clark.
For further information about the development of peanut immunotherapy and when it will become available in clinics, please register your interest on www.cambridgeallergytherapy.com.