A study presented at this year’s American Academy of Allergy, Asthma & Immunology Annual Meeting showed that many patients learned of their sesame allergy only after having been diagnosed with another food allergy. Only one-third had reported having a prior reaction to sesame.
The study — the largest retrospective study of sesame-allergic patients — also showed that sesame allergy was less likely to resolve among patients with concomitant peanut and tree nut allergies.
“Sesame allergy is a growing concern in the U.S. and elsewhere and its prevalence is on the rise,” Dr Rima Rachid, Director of the Allergen Immunotherapy Program and Co-Director of the Food Allergy Program at Boston Children’s Hospital, told Healio.
Rachid and colleagues analyzed the data of 1,394 patients from the Informatics for Integrating Biology and the Bedside (i2b2) dataset to identify all sesame-allergic patients who were evaluated at Boston Children’s Hospital allergy program. The study population was 38.1% female with a mean age of 4.2 years. Mean follow-up was 4 years.
53% underwent sesame testing after having been diagnosed with another food allergy and 94% had a concomitant peanut or tree nut allergy.
Said lead study author Dr Farida Abi Farraj, MD, a postdoctoral research fellow at Boston Children’s Hospital:
Previous studies have demonstrated a serological or clinical cross-reactivity between peanut, tree nut and sesame allergy. Other studies also demonstrated cross-reacting allergens between sesame and tree nut or sesame and peanut, which could explain why these allergies are co-occurring.
We also think that there is likely increase testing for sesame allergy when patients present with peanut and/or tree nut allergies.
The researchers found that patients commonly had allergic rhinitis (67%) and eczema (73%).
Only 37.2% of patients experienced at least one prior reaction to sesame with 9.8% having suffered anaphylaxis.
Only 8.4% of patients had documented resolution of their sesame allergy, with resolution less likely to occur among those with an ongoing history of peanut or tree nut allergy or who had a history of sesame reactions.
Said Abi Farraj:
It is unclear how many of these patients are sensitized without clinical reactivity (ie, they have a false-positive result, are falsely diagnosed and would not react when given sesame) and how many are truly allergic. It is critical to evaluate these patients further by performing food challenges, especially when their sesame skin test wheal results are not too large and/or their serum sesame IgE is not too elevated.
A low number of patients undergo a food challenge, which implies that further discussion with patients and their families is warranted about the possibility of doing food challenges and identification of reasons for not doing them.
Note that sesame is not a “Top 8” allergen as classified by the US Food & Drug Administration, and so can be hidden as an ingredient under blanket terms such as “spices” or “natural flavorings”. As a result of the passage of the FASTER Act, sesame will become the FDA’s ninth top-allergen and need to be labeled separately as an ingredient beginning in 2023.
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