Peanut allergy increasing: Australian study
27th of February
The authors made a conservative estimate that the incidence of peanut allergy by the age of six years in ACT children had more than doubled in children born in 2004 (1.15 per cent) compared to those born 1995 (0.47 per cent).
“‘Generation A’ – the ‘allergy generation’, has already been born. A failure to act now means that future generations will have an even higher price to pay,” says Canberra-based clinical immunologist Dr Raymond Mullins.
Allergic disease is a major public health issue in Australia and New Zealand, and one that government has ignored too long.
Dr Mullins and colleagues, whose study will be published in the March issue of The Journal of Allergy and Clinical Immunology, examined the characteristics of 778 patients with confirmed peanut allergy over the 13-year period from 1995 to 2007.
They found no significant changes in the clinical features of peanut allergy: most peanut allergy (90 per cent) developed by six years of age, and the severity and age of the first reaction remained unchanged.
Serious allergic reactions were found to be unpredictable. About a third of subjects who had dangerous reactions had previously had milder reactions. However, having asthma and having a first reaction at an older age were both associated with a greater risk of more serious allergic reactions (anaphylaxis).
“The fact that severity did not change undermines the community perception that the argument that the increase is the result of anxious parents presenting with milder cases. The increase is real, and for 80 per cent of those affected, they will still be allergic for decades to come,” says Mullins.
In the long term, we need to invest, identify and intervene, he says.
“We call on our health care planners to invest heavily into epidemiological research to identify the factors that have led to this food allergy epidemic in the last decade. We need to identify causative factors to design preventative strategies to stem the ongoing increase, and we need encourage intervention studies to treat established disease”.
Mullins’ study comes hot on the heels of a UK study, which successfully desensitised a small group of peanut allergy sufferers.
The research, carried out at Addenbrooke’s Hospital in Cambridge, involved the patients eating daily doses of peanut flour. At the start, all of them risked a trip to A&E of they encountered a peanut — but by starting with a tiny 5 milligram serving and slowly building up over six months, they trained their bodies to tolerate at least 800 milligrams: 160 times the starting dose and equivalent to five whole peanuts.
Dr Jan Sinclair, paediatric immunologist at Auckland’s Starship Hospital, says the study is promising and one of many, which also include milk and egg, being carried out in Europe and the US.
Once more study is carried out, it will be a question of whether our health system has the capacity to undertake food desensitisation programmes, she adds.
This success of this programme offers hope to food allergy sufferers, but it’s important to realise this research is in its early stages, warns Allergy New Zealand, a national charity that offers support to allergy sufferers.
“This research, although extremely promising, is in its early stages and much more needs to be done before this treatment can be offered to peanut allergy sufferers in New Zealand,” says the organisation’s chief executive, Penny Jorgensen.
“It’s an exciting development, but we are cautiously optimistic until more studies of this kind are carried out. Also, whether our health system would ever be equipped for this sort of treatment is an important factor.”
Our health system really underestimates the burden on people living with life-threatening food allergies, Jorgensen adds.
“If Pharmac can’t even afford to fund the EpiPen, an andrenaline auto-injector necessary in the treatment of anaphylaxis, then what hope do we have of being able to afford desensitisation treatment?”
And a word of warning: do not be tempted to try this at home, Jorgensen adds. “The treatment for food allergy continues to be strict avoidance. The researchers are carrying out their treatment under strict medical supervision, where the risk of anaphylaxis in the build-up phase is great.”
Previous peanut allergy desensitisation programmes in the 1990s produced serious side-effects and were not successful. These attempts used peanut allergy injections rather than the more gentle oral doses tested in Addenbrooke’s study, and doctors say that difference may have played a role in the making the new approach so much more effective.
Four patients took part in the initial research, which is published this week by the journal, Allergy, and a further 18 children aged seven to 17 are now successfully following the programme. All the original patients are now eating at least five peanuts a day to help their body maintain its ability to tolerate the food, and with doses that large both they and their families know that they can live a normal life and be safe — even if they eat a peanut by accident.
Researchers say there is no reason why the programme can’t be extended to include adults — so with appropriate medical treatment, a previously untreatable fatal allergy could become a thing of the past for thousands of the UK’s most severely affected patients.
Dr Andy Clark, who led the research, says: “Every time people with a peanut allergy eat something, they’re frightened it might kill them. Our motivation was to find a treatment that would change that and give them the confidence to eat what they like. It’s all about quality of life.
“Peanut allergy is common — it affects one in 50 young people in the UK — and unlike other childhood food allergies like cow’s milk, it rarely goes away. For all our participants, a reaction could lead to life-threatening anaphylactic shock — but now we’ve got them to a point where they can safely eat at least 10 whole peanuts. It’s not a permanent cure, but as long as they go on taking a daily dose they should maintain their tolerance.”
The study was carried out in the hospital’s Wellcome Trust Clinical Research Facility, and was sponsored by the Evelyn Trust, a Cambridge charity that supports medical research.