Allergy Update: A new primer for food allergy

Bowl of shelled peanutsPeanut allergies continue to receive a large amount of negative attention across both traditional and social media channels, but as a new comprehensive review illustrates, positive steps are being made to counter misinformation about allergies among consumers. In the article below, by Dr. Andrew Craig, Health Consultant for the American Peanut Council, we examine the results of this promising review from The Journal of Allergy and Clinical Immunology by allergists Hugh Sampson and Scott Sicherer.

Read the full review here.



A new primer for food allergy
by Dr. Andrew Craig

That’s what Hugh Sampson and Scott Sicherer, allergists from Mount Sinai in New York City, are calling their 18-page comprehensive review in the latest Journal of Allergy and Clinical Immunology. They did similar reviews in 2014 and 2006. Since then, so much has changed in the food allergy landscape. There are no fewer than 224 studies referenced in the 2018 review. Anyone new to the world of food allergy could reliably start here in the company of authoritative guides.

Peanut allergy’s profile has been high since 2014 and reported world food allergy trends are upwards, so it’s no surprise to see peanut allergy research prominent in the review. The LEAP study, reporting in 2015 that high risk infants aged 4 to 11 months consuming peanut protein at least three times weekly until age 60 months were far less likely to develop peanut allergies than infants who had complete avoidance. And the 12-month follow-up study, LEAP-On, showed the hugely encouraging finding that tolerance to peanut allergen lasted for at least a year. The parallel EAT study found lower rates of food allergies with early introduction of allergenic foods in breastfed infants and also the vital lesson that parents needed help to get things right and sustain the effort.

There is growing interest in adult food allergy onset. Why serious food allergies start in otherwise healthy adults remains puzzling, especially as it tends to be foods like shellfish, tree nuts, fish and soy, rather than peanuts, which cause the most reported cases.

The reviewers highlight the enduring importance of the clinical history and food challenges in making an accurate diagnosis. This wisdom is confounded by the rising tide of testing kits and their inappropriate use leading to false positives (skin prick test sensitivity is not clinical allergy). Exaggerated prevalence figures may result from so-called tests with no scientific validity but easy online access. They put it bluntly: “The greatest source of misdiagnosis in food allergy might well be the lack of appreciation that a positive test result (sensitization) does not equate with allergy and that indiscriminate ‘‘panel testing’’ can result in a disaster of misdiagnosis” especially if there is a lack of confidence in interpreting the results.

Online allergy-related services continue to drive change, for good and ill. There is already a high level of social media use in the food allergy community for information and management advice. When that conflicts with a professional care giver, research suggests a growing number of people are choosing to follow the online advice. So it is incumbent on all organisations to be accurate and evidence-based in the information they provide. As more apps for food allergy come into the market, this trend is likely to increase, though their consequences for safety are unknown.

The vexed question continues of whether precautionary “may contain” labelling benefits consumers or industry, given its frequent ambiguity about communicating actual risk, and what should replace it that is reliable, safe and trusted. No consensus exists – yet – to answer to that question. And a worrying parallel finding is that AAIs are either not accessible or under-used in many serious incidents. A 2017 survey of US food allergic college students found only 266 of 748 carried adrenaline/epinephrine self-injectors and only half had them available at all times. This young adult risk taking is not confined to North America.

The review highlights that food bans are not evidence supported. In a 5-year study of Massachusetts public schools, no policy regarding peanut restrictions was associated with absence of reactions, and epinephrine (adrenaline) administration rates were not different when comparing schools with various forms of restriction. Recent Canadian research echoes this.

The experts are getting the message about early introduction and prevention. But what about health professionals – and through them parents – at the grass roots? It is essential that they appreciate what is changing, since – as the reviewers stress – “The strongest current evidence for prevention is regarding early introduction of peanut for infants at high risk”. That is where parents need well informed and supportive help to stop food allergies developing. They may not be getting it and not just in developed countries. Recent reports suggest that affluent urban parents in China and India are strongly reluctant to introduce allergenic foods such as seafood and peanuts to their infants, so as food allergy rates are rising in those countries they may be repeating the errors we are only just starting to exit from.

With prevention the ultimate goal, the therapeutic domain for established allergy is also ramping up. Sicherer and Sampson observe: “With numerous studies ongoing and planned with OIT, EPIT, SLIT, modified subcutaneous immunotherapy, DNA-based vaccines, and various biologics and other approaches, we are clearly at the precipice of entering a promising new landscape in which we will be truly treating and not just managing food allergies.”

The 2018 review isn’t a light read but it is hugely valuable. Given the rate at which knowledge of prevention and treatment of food allergy is expanding, the authors may have to reconsider whether they can wait another four years before doing a successor piece. They say they would welcome that and we should take that as a sign that things are definitely moving in the right direction and at a quickening pace.

Source: Sicherer SH and Sampson HA, 2018 “Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and Management” J Allergy Clin Immunol 141: 41-58. Free to download: