Allergic begins with a minute-by-minute account of a man in a car having an allergic reaction to a bee sting. Author Theresa MacPhail is coolly scientific as she describes anaphylaxis progressing through his body, the rising panic of his helpless girlfriend and the firm resignation of the pharmacist who refused to give him adrenaline because the law forbade it. The man in the car was MacPhail’s father, and he died that day. The book continues, describing the science, politics and personal experience of allergies in the same matter-of-fact tone, with the same sense of building to a grimly inevitable conclusion. Allergic people, MacPhail says, are the “canaries in the environmental change coal mine”; the way we live is making allergies worse.
MacPhail, a medical anthropologist, has spent years researching allergies: what they are, why we have them and what, if anything, we can do to avoid them. The task is difficult because of the lack of standardisation of almost everything. The levels of allergens in skin-prick tests vary widely. So do immunotherapy treatments. Experts she spoke to couldn’t even agree what an allergy was. In one study, depending on which definition was used, “up to 39% of children went from having asthma to not having it”. Almost everyone she interviewed agreed that allergies are becoming both more prevalent and more severe, but there’s no agreed-on way to measure them.
It seems that some humans have always had allergies. The Egyptian king Menes is thought to have died from an insect sting in around 3000BC. They were defined, medically, in 1819, and the first skin-prick test was developed in 1865, not having improved much in accuracy since. But in our modern, industrialised world, allergies have escalated. Hay fever rates increased first, “then asthma began to spike in the 1960s and 70s, and then eczema and food allergy rates reared their ugly heads in the 1980s and 90s.”
MacPhail attributes this to a complicated combination of genetic, environmental and human-made factors. She explains how pollen and diesel particulates interact to make allergic conditions more likely, and how climate change lengthens pollen seasons and introduces new allergens into our systems. As the world becomes increasingly developed, everything from the crops and trees we grow to the fuels we burn to the chemicals we use and the bacteria and fungi we encounter plays a role in our health. Some of these factors we can do something about: “research suggests that less frequent changing of bed linens may be beneficial to the health of our nasal and airway microbiome”. Others are harder to address, such as the worrying finding that “kids who were exposed to the highest level of air pollution early in their life were more likely to develop asthma by age seven”.
In a booming market, allergy medicine is big business, and that raises tough questions about how to care for people whose health is damaged by the way we all live now, and who should pay for that care – especially as experts believe that by 2030 50% of the world’s population will have allergies. MacPhail finds that in the US 52% of adults with life-threatening allergies don’t carry the EpiPens they have been prescribed. “As an interesting and pertinent aside,” she writes, “while researching this book, I learned new information about my father’s death … His doctor had given him a prescription for an EpiPen … But [his] insurance would not cover the cost.”
There is some good news, mostly in the form of Dupilumab, a new antibody treatment for eczema and maybe more. (“It was the itch data that blew us away”), boasts the company that makes it. But on the whole, MacPhail is not optimistic. Changing our sheets is one thing. If we really want to prevent allergies ruining more lives, we’re going to have to completely change the way we live.
• Allergic: How Our Immune System Reacts to a Changing World is published by Penguin (£25). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.
