Prevalence of IgG-mediated food intolerance among patients with allergic symptoms

BACKGROUND: Food intolerance mediated by food specific IgG antibodies has been implicated in a variety of disorders. OBJECTIVES: To assess the prevalence of food specific IgG antibodies among patients clinically presenting with allergic symptoms lacking laboratory evidence of allergy. DESIGN: Descriptive retrospective cross-sectional study. SETTING: King Khalid University Hospital, Riyadh between 2010-2015. PATIENTS AND METHODS: Patients were screened for food specific IgG antibodies. All symptomatic patients lacking laboratory evidence of allergy who underwent food specific IgG testing during the study duration were included. MAIN OUTCOME MEASURE(S): Levels of IgG antibodies in patients with unidentified allergic symptoms. RESULTS: We selected 71 patients with allergic symptoms lacking laboratory evidence of allergy. There were 49 female and 22 male patients mean age 38.8 (16.0) years. The majority (85.7%) had urticaria. The most frequently occurring food specific IgG antibodies were against cola nut in 80.3% of patients followed by yeast in 78.9%, wheat in 77.5%, red kidney bean in 71.8%, pea in 63.4%, corn in 62% and egg white in 62% of the patients. Compared with male patients, females harbored significantly higher food specific IgG antibodies for frequently occurring food materials, particularly against wheat (74% vs 25.5%; P<. 0001), corn (77.3% vs 22.7%; P<. 0001) and cola nut (71.9% vs 28.1%; P<. 001). Patients aged less than 40 years had higher levels of food specific IgG against gliadin (P<. 003), egg white (P<. 03) and barley (P<. 05) compared with older patients. CONCLUSION: The detection of a variety of food specific IgG antibodies among patients with allergic symptoms indicates a possible link to food intolerance allergy. Females are prone to develop food intolerance more than males. LIMITATIONS: Difficulty of comparison of results with previous studies because of lack of data. Follow-up studies could not be performed to assess the effects of elimination from the diet due to limited time allocated for this study.