The public hysteria over severe peanut allergies raised my skeptical hackles recently. Following a discussion with one of the teacher assistants at work last week, in which she tired to argue with no clear understanding of the issues or even the scantest anecdotal data, that we should ban nuts from the school, I decided to try and gather some evidence and look at the subject objectively.
The type of allergic reaction that is the source of the public panic is that which results in anaphylaxis. According to the website of The Australasian Society of Clinical Immunology and Allergy anaphylaxis is “a generalised allergic reaction, which often involves more than one body system (e.g. skin, respiratory, gastro-intestinal, cardiovascular). A severe allergic reaction usually occurs within 20 minutes of exposure to the trigger and can rapidly become life threatening.”
Symptoms include:
- Difficulty and/or noisy breathing
- Swelling of the tongue
- Swelling or tightness in the throat
- Difficulty talking or hoarse voice
- Wheeze or persistent cough
- Loss of consciousness and/or collapse
- Pale and floppy (young children)
Without treatment it frequently results in death.
It is natural that parents would want to protect their children from harm. This instinct is something that most higher-order animals exhibit. The human capacity for thought takes the protection that our young are offered far beyond immediate threats to imagined threats and this is no bad thing as it protects against potential dangers and is no doubt one of the factors that has allowed our species to thrive. Unfortunately when fed with faulty data this protection instinct malfunctions and, as is the case with peanut allergies, does more harm than good.
Discovering what might be termed “evidence” on the subject of peanut allergies is actually quite difficult because the facts have a hard time making themselves heard over the shrill cries of “Think of the children! Oh, the humanity!”. Still as I fully expected it seems that there is no cause to panic.
Statistics on childhood food allergies are tricky to find and different sources often quote different figures. Dr. Andrew Kemp, Professor of Allergy Immunology and Infectious Diseases at The Children’s Hospital at Westmead, in a letter to the Medical Journal of Australia in 2005 cited a number of studies a concludes that in the Australian child population the risk of severe allergic reaction to peanuts would be 0.2 – 0.25%, or 2 in 1000. A British study found that between 1992 and 2002 there was an equivalence of 6 deaths per 100 million children from severe allergic reaction to food.
Cited here , here and here Nicholas A Christakis’s piece in the British Medical Journal compared the number of deaths from all food allergies in adults and children in the United States each year, 150, with other causes of death such as the 45,000 people who die in motor vehicle accidents, the 2000 who drown or the 1,300 who die in gun accidents. Christakis is one of the few few voices of reason likening hysterical responses to peanuts such as evacuations, nut-free schools and school entrances admonishing people to “wash their hands to avoid contamination” to MPI (mass psychogenic illness, previously known as epidemic hysteria).
Australian statistics are particularly hard to come by. The Australian Bureau of Statistics 2006 Year Book offers data on child injury deaths, but nothing on death due to other causes. I did find data that indicates a death rate of 15 in 100,000 for Australian children in 2006. Based on a population of 4 million children aged between 1 and 14 this means approximately 600 children die each year from all causes.
One has to question the lack of specific statistics on the Australian Society of Clinical Immunology and Allergy (ASCIA) website. Surely if the problem were as widespread as the amount of public concern would indicate then they would make the statistics available. I do not wish to imply that ASCIA are overstating the problem or feeding the hysteria, however. In fact ASCIA seem to promote what most experts in the field advise – taking steps to ensure that procedures are in place for those children who are identified as having a severed allergy to peanuts so that if they are exposed to their allergen and develop anaphylaxis it is not fatal.
The rise in the incidence of peanut allergies cited by some sources may actually be the result of non-exposure to the allergen early on. The Age, May 19, 2006, quotes Associate Professor Dr Mimi Tang of the RCH allergy department who states that “[peanut allergies] are increasing in prevalence”.
According to the article Dr Tang said that peanut allergy was part hereditary, with children born to allergy-prone parents more susceptible to the condition, but environmental factors, including the western world’s culture of cleanliness, have also contributed – with reduced exposure to germs causing some children’s immune systems to react to otherwise harmless antigens. This is borne out by a study cited in The Guardian where researchers at Guy’s Hospital in London found that “children who eat few or no peanuts when they are babies are 10 times as likely to develop peanut allergy later in life”.
The researchers questioned 5,000 children in London and Tel Aviv. In Israel peanuts are are much used weaning food, whereas in Britain parents have been warned to keep young children away from nuts. The original study can be found here.
As mentioned above the most sensible approach, once a child has been diagnosed as having severe peanut allergy using a skin-prick test, is to take appropriate steps to ensure their safety. ASCIA has some excellent information and resources for parents and schools on coping with food allergies.
One last point of interest is this. A group of parents in Canada are taking a reasonable, rational response to peanut allergies by advocating reasonable risk management. Perhaps this is the start of the turning of the tide of the mass hysteria surrounding peanuts.
* Mandatory weak nut pun
