This guest post was written by Theresa MacPhail—assistant professor in the Science, Technology, and Society Program at Stevens Institute of Technology.
Last December, I wrote a blog post about the early history of food allergies from the 1800s through the 1960-70s. In this installment, we’ll examine more recent food allergy chronicles, current treatments, and diagnosis debates. Despite advances in our understanding of the immune system, and promising developments in allergy-related technologies (like the Allergy Amulet), the lack of a cure or effective treatments for food allergies persists.
The Discovery of IgE
Immunotherapy treatments were first tested in animals, and then cautiously applied in clinical settings to treat both respiratory allergies and food allergies beginning in 1911. The risk of an accidental anaphylactic response was, and is, ever present. Much of the early allergy testing and treatment remained unchanged until the mid-1960s, when two separate research teams discovered immunoglobulin E, or IgE—a molecule that naturally forms in human blood.
IgE’s discovery led to a greater understanding of the inflammatory response that follows allergen exposure, sparking more research around the cause of allergic reactions. By 1975, the first commercially available and reliable blood test for IgE became available for clinical use. IgE testing quickly became a significant aid in allergy diagnosis, since an elevated presence of IgE levels in the blood often indicates a food allergy.
IgE has played an enormous role in subsequent allergy research, diagnosis, and treatment. However, while IgE tests provide information as to the likelihood of having a food allergy, 50-60% of IgE blood tests yield a “false positive” result, creating a great deal of uncertainty in diagnosis. IgE as an allergy biomarker is accordingly far from perfect.
Food Allergies - A Rising Prevalence?
If you follow the news or social media, or have a young child in the school system, it certainly seems that food allergies are on the rise. Although food allergy awareness has increased over the last decade and has become a more popular topic of conversation, the food allergy prevalence rate has been difficult to measure with confidence.
Figures on the national and global food allergy population are unsettled. This is largely because the numbers rely on multiple data sets collected across different methods and research groups. Official estimates place the figure at around 15 million. Adding to this confusion is the difficulty in confirming the presence of an allergy with current diagnostic tools (often IgE testing, discussed above). The majority of food allergy and food intolerance cases depend on self-reporting and sometimes self-diagnosis—and those numbers fluctuate greatly. A recent paper looking at multiple different allergy studies found that “[s]elf-reported prevalence of food allergy varied from 1.2% to 17% for milk, 0.2% to 7% for egg, 0% to 2% for peanuts and fish, 0% to 10% for shellfish, and 3% to 35% for [other foods].” A 2013 paper further suggested that “at least 1%–2% and up to 10% of the US population suffers from food allergies," which based its findings on "self-report, skin prick test (SPT), serum-specific IgE (sIgE), and oral food challenges (OFC).” These reports show that food allergy populations vary based on allergy type, reported severity, geographic region, study design, and testing method.
In short, with no easy and standardized way to diagnose food allergy cases, it is difficult to confirm and measure the perceived rise in the food allergy population.
The LEAP Study and the Future of Oral Immunotherapy
Perhaps the most significant study on food allergy in the last 50 years is the Learning Early About Peanut Allergy (LEAP) study by the Immune Tolerance Network. In this study, infants at a higher risk of developing a severe allergy to peanuts were randomly assigned to one of two groups: one that would avoid ingesting peanut-containing foods until age 5, and one that would consume a peanut-containing snack (~6 grams of peanut protein) with three or more meals per week until age 5. Of the children who avoided peanut, 17% developed a peanut allergy, compared to only 3% of the children in the control group. In a press release for the study, one of the researchers noted how for decades allergists have recommended that infants avoid consuming allergenic foods, and this study "suggests that this advice was incorrect and may have contributed to the rise in  peanut and other food allergies.” Indeed, the LEAP study overturned decades of prior advice and shook the allergy research community. The study also gave credence to one of the oldest forms of allergy treatment: immunotherapy.
After a decade of research, oral immunotherapy is becoming more widely accepted as effective for the most common food allergies (e.g., peanut), but little is known about its long-term effectiveness. If you’re not familiar, oral immunotherapy (OIT) is a method of food desensitization that involves re-introducing the immune system to the allergenic food in gradually increasing amounts over time, with the goal of eventual tolerance. Although researchers are optimistic about its potential, it is not without its drawbacks. You can learn more about OIT in Allergy Amulet’s blog post here.
The Promise and Peril of Epinephrine
Epinephrine (the hormone adrenaline) was first discovered in 1900 and marketed to treat asthma attacks and surgical shock. By 1906, with the development of a synthetic version, the drug was in common use by clinicians to treat severe asthma attacks. Immunologists and allergists experimented with dosages in the decades following, standardizing treatment protocols.
In 1975, a biomechanical engineer developed the first auto-injector syringe for the military, which was then adapted for use with epinephrine. It wasn’t until 1987, however, that the FDA approved the first epinephrine auto-injector for the general public. Epinephrine auto-injectors proved so effective—and the dosage delivered was so consistent—that it became the standard prescription for anyone suffering from a severe allergy. By the 1990s, food allergy patients were advised to carry one at all times for their safety.
In 2016, the mother of a child with a severe food allergy began a campaign against the dramatic rise in price of one of the most popular epinephrine auto-injector brands: EpiPen. The price of EpiPen surged between 2004 and 2016 – increasing from $100 to over $600. With few competitors on the market, Mylan Pharmaceuticals, the manufacturer of the EpiPen, felt no need to lower its prices. The story went viral and sparked debate about pharmaceutical industry pricing policies and access to affordable healthcare. Since the scandal broke, there has been a call to develop alternative and less expensive epinephrine auto-injectors.
The Epi-Pen story—and this post—highlight the urgent need for greater investment in allergy research and innovation. Let’s hope that with new advancements in the coming years, food allergy itself will be history.