A recent study suggests the condition may one day be treatable. What are the causes of peanut allergy – and how far off is a cure?
Allergy to peanuts has doubled in the past five years and affects at least one in 100 children in Europe and America. While allergic reactions aren't all fatal (they may cause a rash and vomiting), no parents would risk a full-blown reaction. So there has been much interest in the results of a recent study that suggests the condition may one day be treatable. The aim is to help a child survive eating a peanut by mistake, rather than enabling them to scoff a Snickers bar.
The research, published in the Lancet, divided nearly 100 children into one group that avoided peanuts, and another given increasing amounts of peanut flour daily. After six months, 91% of those given peanut flour could tolerate up to 800mg a day (equivalent to five peanuts). Some children had side-effects such as sickness and mouth itching. One child needed adrenaline. But overall, the children felt their quality of life was better.
So does this study mean we might be able to treat peanut allergy, and does it help us understand the causes?
I cannot emphasise enough how you should not try copying this study at home, because a severe allergic reaction can be fatal. The answer currently is no, you can't treat peanut allergy. This study was done under medical supervision in a research lab. It is promising, but Dr Matthew Greenhawt, who wrote an editorial on the study in the Lancet, says that such a treatment (oral immunotherapy) is years away, because there is no evidence for how long the effects last and bigger trials are needed. He says rates of peanut allergy are rising because peanuts are used in so many foods. Our immune systems have fewer infections to fight due to better hygiene, and now overreact when faced with inflammation from an allergic reaction.
Meanwhile, research is challenging other assumptions about peanut allergy. A paper in the Journal of the American Medical Association last year found that pregnant women should not avoid peanuts, because doing so didn't reduce – and might actually increase – allergy rates.
There is still conflicting advice as to whether only children over three should eat peanut products. Researchers from King's College London (funded by the National Peanut Board in America) pointed out that countries in which young children eat peanut products had low rates of peanut allergy. They compared children in Israel with those in the UK – 69% of the former had eaten something containing peanuts by nine months, compared with 10% of the latter. UK children had 10 times the rate of peanut allergy.
Allergy specialists are waiting for the results of the Leap trial, which is due to report its findings this year or next on the right age to introduce peanuts.
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