It is allergy season once again. If you are one of the 81 million Americans with hay fever, spring is a mixed blessing. Yes, the days are longer, but they are accompanied by itchy eyes, runny noses, and an endless hunt for antihistamines. On days when the pollen count is highest, seasonal allergies are like an assault—from the outside world, but also from our own bodies’ immune systems going into overdrive.
There are growing numbers of allergy sufferers, too. In 1997, around 0.4 percent of US children were reported to have a peanut allergy. By 2008 the figure was 1.4 percent. In the UK, hospital admissions due to severe food allergies tripled between 1998 and 2018. And although rates of asthma—often triggered by allergies—have leveled off in the US, they are continuing to rise globally thanks to increased rates in the developing world. We’re also seeing a rise in unusual allergies, such as alpha-gal syndrome, where some people bitten by lone star ticks develop strong reactions to red meat.
Looking at the rise in allergies, it’s hard to shake the feeling that something is out of kilter. Either it’s the outside world, our bodies, or the complex interaction between the two, but something is going wrong. The question is why—and what can we do about it?
A good place to start is by figuring out what the hell allergies actually are. In her book Allergic: How Our Immune System Reacts to a Changing World, medical anthropologist Theresa MacPhail attempts to do just that. One theory is that allergic reactions evolved as a way for the body to expel carcinogens and toxins—from insect stings to snake bites. Even a few centuries ago, an extreme immune response to a potentially fatal snake bite might have been a useful way for the body to respond, one researcher tells MacPhail.
As the world has changed, our overactive immune systems have started to seem decidedly out-of-step with the threats we face. It doesn’t help that growing seasons for crops are getting longer, exposing people to pollen earlier each spring. At the same time, changing diets and lifestyles are putting our microbiomes out of whack, perhaps making children more likely to become sensitized to food allergens. Stress might also influence our susceptibility to allergies—we know that stress hormones provoke a similar kind of response in mice cells as allergic stressors.
If this is sounding a bit inconclusive, then you’d be right. As MacPhail discovers, it’s hard to pin down exactly what is causing the rise in allergies—doctors don’t even completely agree on what an allergy is or how best to diagnose one. But MacPhail has a good reason to dive into these complexities. In August 1996, her father was cruising down a New Hampshire road on his way to a beach with his girlfriend. A solitary bee flew through the open sedan window and stung him on the side of the neck. Soon afterward, her father died from anaphylactic shock; he was 47. “You are really here today because you want to know why your father died,” one allergy doctor tells MacPhail during an interview.
But in the world of allergy research there are no easy answers. Maybe it was genetic, or the fact that her father wasn’t carrying a potentially lifesaving EpiPen, or that the pharmacist on duty at the drugstore wasn’t allowed to inject him with adrenaline, or that he was sensitized to bee stings during his two tours of duty in Vietnam. Maybe he was just unlucky.
This is the thread that runs through Allergic: The answers we reach tell us everything about how we view the world. At the turn of the 19th century, some Harvard researchers thought that asthma in children might be caused by a “fixation of hate subconsciously directed toward the mother.” Allergy sufferers tended to be white, urban, and educated, and often they were young boys or women—people deemed to be prone to neurosis and imbalance. Some of this stigma today still lurks in people who accuse allergy sufferers of “faking it” or who roll their eyes when plane attendants announce they won’t be serving nuts on a flight.
Our own biases are also on display when we think about solutions to the rise in allergies. Until very recently, the world of allergy treatment has moved at a glacial pace. Antihistamines were discovered in 1937, and since the 1940s they’ve been the main treatment for allergies, even though researchers acknowledge they have major shortcomings. Now a new range of treatments is coming to the fore. In January 2020, the US Food and Drug Administration approved the first oral immunotherapy allergy drug, Palforzia, which works by exposing people to a gradually increasing amount of peanut allergens over time. There are also new “vaccines” being developed to immunize people against bee stings, although these require 50 injections over a long period of time.
It’s not just new drugs we need—we need to change the world in which they exist. Alpha-gal syndrome is becoming more common because the range of habitats for the lone star tick is expanding as the world warms; extended pollen seasons are the consequence of climate change and the introduction of plant species into places they never existed in before. Money matters, too. Injectable adrenaline, sold in branded form as the EpiPen, can help people survive severe allergic attacks, but the pens are so expensive—roughly $600 for two injectors—that many people who should carry an auto-injector simply can’t afford to. Better food labeling and production can cut down the risk that children will have deadly reactions to prepackaged foods, but only if companies are on board with the change.
“Allergy is ultimately about our human vulnerability, both biological and social,” MacPhail writes. It’s about problems of our own creation and spiraling risks that no one could have foreseen. How we choose to respond is entirely in our hands.