Allergic Rhinitis in Relation to Food Allergies: Pointers to future research

Gut and bladder fermentation syndromes: a narrative review

We recently reported the first clinical case of bladder fermentation syndrome (BFS) or urinary auto-brewery syndrome, which caused the patient to fail abstinence monitoring. In BFS, ethanol is generated by Crabtree-positive fermenting yeast Candida glabrata in a patient with poorly controlled diabetes. One crucial characteristic of BFS is the absence of alcoholic intoxication, as the bladder lumen contains transitional epithelium with low ethanol permeability. In contrast, patients with gut fermentation syndrome (GFS) or auto-brewery syndrome can spontaneously develop symptoms of ethanol intoxication even without any alcohol ingestion because of alcoholic fermentation in the gut lumen. In abstinence monitoring, a constellation of laboratory findings with positive urinary glucose and ethanol, negative ethanol metabolites, and the presence of yeast in urinalysis should raise suspicion for BFS, whereas endogenous ethanol production needs to be shown by a carbohydrate challenge test for GFS diagnosis. GFS patients will also likely fail abstinence monitoring because of the positive ethanol blood testing. BFS and GFS are treated by yeast eradication of fermenting microorganisms with antifungals (or antibiotics for bacterial GFS cases) and modification of underlying conditions (diabetes for BFS and gut dysbiosis for GFS). The under-recognition of these rare medical conditions has led to not only harm but also adverse legal consequences for patients, such as driving under the influence (DUI). GFS patients may be at risk of various alcohol-related diseases.

Fruitful or unfruitful: strawberry and tomato specific immunoglobulin E testing at a tertiary pediatric center

Background

Suspected strawberry and tomato (S/T) food allergy (FA) can be evaluated using specific immunoglobulin E (sIgE) testing despite its low specificity and positive predictive value.

Objective

This study aims to understand ordering patterns for S/T sIgE testing and identify relevant factors to clinical decision-making.

Methods

We retrospectively reviewed 814 patients with sIgE testing available for strawberries (651), tomatoes (276), or both (113) from January 2012 to May 2022 at a tertiary pediatric hospital. Patient demographics, provider specialty, and reasons for testing were collected. Student's t-test and multiple regression analyses were performed to test the association between the S/T sIgE level and clinically relevant outcome (CRO) status. Fisher's exact test and general linear models were used to evaluate and compare potential predictive factors for CRO status.

Results

Allergy and immunology, gastroenterology, and general pediatrics ordered most S/T sIgE testing. Testing was ordered most frequently for non-IgE-mediated gastrointestinal symptoms, mild possible IgE-mediated reactions, and eczema. Testing was most often ordered for infants and school-age children. Mean sIgE levels were higher for S/T tests resulting in a CRO when controlling for other predictor variables (p = 0.015; p = 0.002 for S/T, respectively). Only 2.2% and 5.4% of tests resulted in a CRO for S/T, and severe allergy was rare. Testing for non-IgE-mediated GI symptoms or eczema, or in non-atopic patients, yielded no CROs. Exposure and reaction history of present illness (ERH) was associated with CROs (p < 0.001; p = 0.04) with a high negative predictive value (99.5%; 100%) and low positive predictive value (11.5%; 15.0%). ERH (p < 0.001, η2 = 0.073; p = 0.009, η2 = 0.123) was a more significant predictor than the sIgE level (p = 0.002, η2 = 0.037; p = 0.212, η2 = 0.030) for CRO status.

Conclusion

The diagnosis of S/T food allergy is made primarily based on clinical history. S/T sIgE testing for children and adolescents should be avoided for patients without an ERH and in the workup of non-IgE-mediated GI symptoms. Testing for eczema and non-atopic patients is likely low-yield.

Factors in an Auto-Brewery Syndrome group compared to an American Gut Project group: a case-control study

Background: Auto-Brewery Syndrome (ABS), also known as Gut Fermentation Syndrome, is a rare but underdiagnosed condition. While scores of case studies of ABS are published, only one previous study examined ABS patients’ demographics, health history, lifestyle factors, and diet compared to a control group of household members.

Methods: We designed a case-control study to identify factors that individuals with a diagnosis of ABS and those who live with them might have that differ from a larger general group. We administered a survey to 46 patients known to have a diagnosis of ABS and their household members. Here, we compare our group of survey takers to a cohort of the American Gut Project (AGP) participants (N=11,297) for the 30 questions that were identical.

Results: With a response rate of 88% and using Rank Sum Tests, the data demonstrate that patients with ABS and their household members are more likely than participants of the AGP to own a pet (p=.03 for cat; p=.0001 for dog), get less sleep (p=.0001), and have lesser quality of bowel movements (p=.03). In addition, the ABS group consumes more water (p=.02) and less alcohol (p=.0004), eats at home more often (p=.0056), and reports more aversion to sweets (p=.01). The most striking difference is a higher presence of non-food allergies in all five subcategories of the survey in the ABS group compared to the AGP group.

Conclusion: Patients with ABS and their household members show several significant differences in their lifestyle and health, diet, and medical history compared to a large group of AGP participants. These differences lead to several hypotheses about co-morbidities that warrant further research.

Mechanisms of allergen-specific immunotherapy for allergic rhinitis and food allergies

Allergen-specific immunotherapy (AIT) is currently the only potential treatment for allergies including allergic rhinitis (AR) and food allergies (FA) that can modify the underlying course of the diseases. Although AIT has been performed for over a century, the precise and detailed mechanism for AIT is still unclear. Previous clinical trials have reported that successful AIT induces the reinstatement of tolerance against the specific allergen. In this review, we aim to provide an updated summary of the knowledge on the underlying mechanisms of IgE-mediated AR and FA as well as the immunological changes observed after AIT and discuss on how better understanding of these can lead to possible identification of biomarkers and novel strategies for AIT.