Five years ago, at a San Francisco elementary school, a nurse stood by to ensure that the children scrubbed their hands as they arrived, while their packed lunches were confiscated and searched for nut products. The measures were a precaution to protect a 5-year-old boy at the school who had a severe nut allergy.
In 2006 a town in Connecticut felled three hickory trees more than 60 feet high after a resident learned that the trees leaning over her property produced nuts and complained that they posed a threat to her grandson, who had nut allergies. (Read TIME's top 10 medical breakthroughs of 2008.)
Recently, a Massachusetts school district evacuated a school bus full of 10-year-olds after a stray peanut was found on the floor.
Do these safeguards seem a little, well, nuts? Harvard professor Dr. Nicholas Christakis thinks so. One of Christakis' children attends school in the district that ordered the bus evacuation, and the episode prompted the physician and social scientist — best known for his work on the social "contagiousness" of characteristics such as obesity and happiness — to write a commentary, published in the British Medical Journal, questioning whether these so-called precautions are snowballing into something more like a societal hysteria.
Of the roughly 3.3 million Americans who have nut allergies, about 150 die from allergy-related causes each year, notes Christakis. Compare those figures with the 100 people who are killed yearly by lightning, the 45,000 who die in car crashes and the 1,300 who are killed in gun accidents. As a society, Christakis says, our priorities have become seriously skewed, and it's largely a result of fear. "My interest is in understanding [the reaction to nut allergies] as a spread of anxiety," he says.
Between 1997 and 2007, the number of children under 18 who suffered from food allergies jumped 17%, according to the Centers for Disease Control and Prevention. Experts don't disagree that the incidence of food allergies has increased, but there isn't much consensus as to why. Some researchers suggest that an overly hygienic lifestyle may hamper the body's ability to build up proper immunities; others believe the statistical rise is a combination of a real increase in allergies and an increase in the number of patients seeking diagnosis (i.e., getting allergy tests that turn up very low levels of reaction that might otherwise have gone undiscovered). "You have to distinguish between an epidemic of diagnoses and an epidemic of allergies," says Christakis.
No one would disagree that children who suffer from life-threatening allergies need to be protected, but the growing trend of demonizing nuts only fuels anxiety, Christakis says. Instilling in the general public the idea that nuts are a "clear and present danger" does little beyond heightening panic. "There are kids with severe allergies, and they need to be taken seriously," he says, "but the problem with a disproportionate response is that it feeds the epidemic."
There's even some evidence to suggest that establishing nut-free zones or nut-free schools may be detrimental to children's health, and increases their risk of developing nut allergies. A study cited by Christakis in his article revealed that, of 86,000 Jewish children living in the U.K. and Israel, those who had more exposure to peanuts earlier in life were less likely to become allergic later on. In the U.K., where peanuts are an infrequent part of the diet, nearly 2% of the children studied developed allergies; in Israel, where peanuts are a common part of the diet, from infancy onward, only 0.17% of children had a nut allergy.
But Dr. Robert Wood, chief of the Pediatric Allergy and Immunology department at Johns Hopkins Children's Center, cautions against putting too much stock in such epidemiological studies. "The reality is that the vast majority of kids — 95% plus — have no potential to get peanut allergies no matter what you do," he says, "and there's ½ % to 1% who are going to get it no matter what you do." Although the findings of the U.K.-Israel study are intriguing, he says, they apply to a very small percentage of children, and more research needs to be done to determine the true impact of early nut exposure. (There is a study currently underway, says Wood, but the results won't be available for another three years.)
Despite the occasional cases of nut over-precaution, Wood thinks the public generally approaches the allergy risk with common sense. "There are definitely situations where we see a fear of the allergy that develops far out of proportion to the true risk, but for the vast majority of schools, things are mostly on balance and in perspective," says Wood, who treats some 2,000 allergy patients. Further, he says, it's important to recognize that the appropriate protective measure depends on the age group in question. "We recommend very different approaches between an early preschooler and a late-elementary schooler," he says. "We view preschool children as being at true risk — sharing food, having messy hands. There are many reactions that occur from those kinds of exposures," he says. "I think that having peanut-free preschools is a totally reasonable, justifiable thing to do." For children in the fourth or fifth grade, however, he says minor precautions like specialized seating arrangements in the cafeteria are probably unnecessary.
Still, on blogs run by moms of children with nut allergies, there is a consistent rallying cry for nut-free zones. The concern is airborne nut dust, which can be inhaled, or oily nut residues that can come into contact with children's skin. Wood, who has been allergic to nuts all his life, says these parents' worries may be exaggerated. The danger may depend on the severity of the allergy, but it has much more to do with the degree of contact, he says. "Nut oils or the kinds of things that might be in a classroom — it's very rare for that exposure to cause anything more than a localized reaction," he says. "On the other hand, if you're a preschooler and your hands are in your mouth a lot, all bets are off."
As for nut dust in the air, Wood says it can cause severe reactions — but only under specific circumstances, with high concentrations of nut dust in a confined space. At a baseball game, for example, where nut dust is quickly dispersed in the air, the risk of an allergic reaction is low. But if you linger in the small waiting room of a restaurant with a dish of nuts and servers who keep passing through with plates of nuts, your risk of an allergic reaction is higher, he says.
But like Christakis, Wood cautions against excessive alarm. "It's an unfortunate situation," says Wood, "if a family with an inaccurate perception of the allergy leads a child to believe that a Snickers bar from 50 feet away is a lethal weapon."