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Progress in Treatment of Life Threatening Peanut Allergy
Posted on Mar 25, 2014 by Ruth Loftus
Food labelling legislation, warnings on food packaging about the ingredients inside and the increasingly long clauses explaining what the foods we eat "might contain’’ or “might have come into contact with”. These notifications regularly receive a lot of bad press for being unnecessary, and they are often criticised as yet another example of the UK government going too far in controlling our food intake.
For many people however, these printed messages can be a matter of life and death, especially when it comes to peanuts. Peanut allergies affect between 0.5% and 1.4% of children in affluent countries and are the leading cause of food related allergic reactions in the US. For those whose bodies cannot tolerate peanuts, an allergic reaction can cause a range of inconvenient symptoms such as an itchy rash, swollen throat or low blood pressure. In severe cases, it can cause a potentially life-threatening anaphylactic shock whereby the body releases histamine, causing swelling, difficulty breathing, heart failure, circulatory collapse and sometimes death. Up until recently, parents of children with peanut allergies have had to rely on the strict food labelling cited above to protect their children from ingesting even the smallest traces of peanuts.
However, thanks to a new study, there might be a less stressful way for parents to cope with their children's allergy to peanuts. The study involved giving strictly controlled portions of peanut to children with an allergy so that their bodies would gradually learn to tolerate them. The logic was that this would make them less sensitive to peanuts and therefore less likely to suffer serious allergic reactions.
The method was tested at Addenbrooke's Hospital in Cambridge, UK. The hospital designed a six month trial for 85 children aged between seven and 16 who suffered from peanut allergies. These children were divided into two groups; one group was strictly controlled to avoid all traces of peanut while the other was given peanut flour on a regular daily basis. The first dose of peanut flour was small, measuring only one 70th of a peanut. Every two weeks, the patients were required to visit the hospital to receive their increased dosage while researchers observed them for signs of an allergic reaction. Over six months of hospital visits, peanut flour doses finally reached 800mg, the equivalent of five whole peanuts.
This method is known as oral immunotherapy (OIT). In general, immunotherapy aims to alter the immune system so that it becomes desensitised to the substance that normally causes the allergic response (the allergen). The trials at Addenbrooke's Hospital indicated that 84% of the 85 children who were given peanut flour during the trials were then able to tolerate a 800 mg dosage after six months.
This final stage of the peanut immunotherapy tests (eating just five peanuts per day) might seem quite insignificant to someone who has never encountered health problems from peanuts, but for children whose lives have been previously been at risk from the slightest trace of peanut, the results of the trial could mean a dramatic change in safety and lifestyle. The change in lifestyle is particularly significant for their parents who need not be so overly cautious about their child being accidentally exposed to peanut products or traces at school or at restaurants or elsewhere.
Similar tests have been developed for other allergies, but these have more commonly been carried out by injection and gradually increasing the injected amount of allergen over time. This is not the first time that oral peanut trails like this have been conducted to test allergic children though. In 2009, a similar test was carried out by the same Cambridge hospital. That time, the test involved just four boys age 9 -13 who all had previous health problems due to peanut allergies and had tested positive to having peanut allergy. In that test, the oral immunotherapy treatment was successful, but the test sample was too small to show conclusive evidence and it was reported that further tests with larger groups would be needed in order to see if the success could be replicated with a larger group.
While the results of the latest findings, published in Lancet in 2014, are said to be more reliable as the size of the test group was substantially larger, there are still reservations among professionals. Despite being the first study of its kind to generate such positive results, there are warnings that this progress does not mean that a cure has been found. The trials were actually carried out over two years ago and while some of the children who took part are now able to eat up to 12 peanuts per day without showing any allergic symptoms, it is not known whether this will remain the case in the future. The scientists who conducted the trials have acknowledged that: “if the effects of the treatment wane, children could once again be exposed to risk”.
Moreover, oral immunotherapy is not yet widespread enough to be implemented as standard clinical practice, so there are still high numbers of children with potentially life threatening peanut allergies. Those families who have not yet had the opportunity to trial oral immunotherapy, have been warned that they should under no circumstances attempt to replicate the trials at home with their own tests to increase daily peanut tolerance.
For the time being, these families are asked to be patient and wait for further testing to see if similar tests can become a common allergy therapy in the near future. In the meantime, they are instructed to keep the same diligent attitude towards avoiding traces of peanut and to ensure that they know what to do to treat an allergy emergency if their child accidentally comes into contact with peanut.