<p>Clinical Characteristics and Proposed Wheat-Cofactor Challenge Protocol with a High Diagnostic Yield in Adult-Onset IgE-Mediated Wheat Allergy</p>

Abstract

Background: IgE-mediated wheat allergy in adults can be childhood or adulthood onset. Adult-onset wheat allergy has been reported, but data on clinical characteristics and practical food challenge protocols are scarce. Objective: We aimed to describe the clinical characteristics of adult-onset wheat allergy, laboratory results, and outcomes of a modified 3-day challenge protocol using a combination of aspirin, wheat, and exercise. Patients and Methods: Patients with histories compatible with adult-onset wheat allergy were recruited from Siriraj Hospital, Thailand. Clinical history, skin prick tests (SPTs), and specific IgE (sIgE) levels were ascertained. Patients with no food challenge contraindications were asked to volunteer for wheat challenge. A modified 3-day protocol using 300 mg of acetylsalicylic acid, 60-75 g of wheat flour, and exercise was used for confirmatory diagnosis of conventional wheat allergy (WA) and wheat-dependent exercise-induced anaphylaxis (WDEIA). Results: Thirty-three patients were recruited. The mean age of onset was 29.7 years (SD 10.5). SPTs yielded positivity rates of 9.1%, 84.8%, and 81.8% in commercial wheat, inhouse gliadin, and in-house glutenin extracts, respectively. sIgE yielded a positivity rate of 61% and 88% in wheat and ω5-gliadin, respectively. Eighteen patients underwent oral wheat challenges. Of these, 17 patients (94.4%) had positive challenges leading to definite diagnoses of WA (35%), and WDEIA (65%). One WDEIA patient developed hypotensive anaphylaxis in the protocol. Conclusion: WDEIA was the most common phenotype. Our modified 3-day protocol could differentiate WA and WDEIA and yielded a high positivity rate (94.4%). It should be used cautiously as severe reactions can occur.

Omega-5 and Gamma Gliadin are the Major Allergens in Adult-Onset IgE-Mediated Wheat Allergy: Results from Thai Cohort with Oral Food Challenge

“… 18 Data from our previous study on adult-onset wheat allergy demonstrated a positivity rate of specific IgE (cut-off, > 0.35 kUA/L) for wheat and ω5-gliadin were 61% and 88%, respectively. 8 The definite diagnosis still relies on OFC done under medical supervision. However, the WDEIA phenotype in adult wheat allergy might have negative results with conventional OFC.…”

“…12 Few studies have addressed food allergens in oral food challenge (OFC)-confirmed cases, for which it is very important to confirm the food allergy in adults 13 and no studies have addressed allergen patterns in Thai adultonset wheat allergic patients. In our cohort, 8 we reported a high diagnostic yield of the modified-3-day protocol to confirm the diagnosis of conventional wheat allergy (WA) and WDEIA. A similar protocol, using cofactors, was performed and yielded a similar result.…”

“…The detailed information on the patients in TAWAC was reported in a previous publication. 8 In brief, the inclusion criteria for TAWAC were 1) an adult patient (age 18–60 years) with the onset of first wheat-allergic symptoms occurring after the age of 18 years, 2) a typical IgE-mediated reaction relating to wheat ingestion, 3) a temporal relationship with wheat ingestion, 4) positive allerologic workup with at least 1 of the following, skin tests, specific IgE to wheat allergens using ImmunoCAP with the condition that in the absence of SPTs and sIgE, the patients must have had at least 2 episodes of recurrence, the last reaction of which having occurred within 1 year of the time of recruitment. All participants with no food challenge contraindications were asked to volunteer for a wheat challenge.…”

“…The 3-day modified wheat-cofactor challenge protocols were performed in 18 of 33 patients in our cohort as previously reported. 8 This protocol allowed for exercise-induced anaphylaxis (EIA), WA, and WDEIA to be diagnosed if a positive result occurred on days 1, 2, and 3, respectively. The contraindications of wheat challenges in our study included 1) having a history of severe anaphylaxis to wheat resulting in profound hypotension, neurological compromise, or respiratory failure and 2) having active cardio-neuro-pulmonary diseases, such as coronary heart disease, asthma, chronic obstructive lung disease, epilepsy, or psychiatric diseases.…”

“…[5][6][7] A distinct phenotype called "wheat-dependent exercise-induced anaphylaxis (WDEIA)" 4 was reported to be common in adolescents and adults and was also found in the majority of patients in the TAWAC. 8 WDEIA could occur with the presence of cofactors other than exercises, such as pollen exposure, concomitant ingestions of non-steroidal antiinflammatory drugs (NSAIDs) or alcohol, the presence of menses in females, infection, and stress. [9][10][11] The IgE response was diverse among the clinical phenotypes (ie, conventional wheat allergy vs WDEIA), geographic distribution, and unique clinical conditions (eg, hydrolysate wheat protein in Japanese adults).…”