Revisiting Fruit Allergy: Prevalence across the Globe, Diagnosis, and Current Management

Is hen's egg a significant allergen in adults too? Findings from an investigation into food allergy prevalence

INTRODUCTION

Data on adult food allergies (FAs) remain limited compared to the pediatric population, and this study investigates the prevalence and clinical characteristics of FAs among adults.

METHODS

This retrospective study included adults aged 18-80 diagnosed with FAs at the Immunology and Allergy Diseases Clinic of Ankara Bilkent City Hospital, Turkey, between 2019 and 2024.

RESULTS

During the study period, 10,505 patients were examined to diagnose and manage various allergic and immunologic conditions. Among these, 563 patients were suspected of having FAs, which was confirmed in 33 patients (mean age 34.74 ± 12.57 years; 60.6% female), yielding a frequency of 0.31%. The primary allergens identified included hen's egg (n = 6, 18.2%), fish and shellfish (n = 4, 12.1%), and various nuts such as peanuts (n = 2, 6.1%), hazelnut (n = 1, 3.0%), and almond (n = 1, 3.0%) as well as seeds like sesame (n = 2, 6.1%) and sweet corn (n = 2, 6.1%) and fruits such as banana (n = 4, 12.1%) and kiwi (n = 4, 12.1%). The median time interval between food consumption and allergic reactions was 10 minutes (2-120). Anaphylaxis was the most frequently observed clinical presentation (n = 24, 72.7%). Emergency treatments included antihistamines and steroids (n = 15, 65.2%), antihistamines, steroids, and epinephrine (n = 5, 21.7%), or epinephrine alone (n = 3, 13.0%). Egg allergy was the most prevalent allergen (n = 6, 18.2%), characterized by a rapid onset of allergic reactions (median of 5 minutes); two patients reacted regardless of cooking methods and four showed tolerance to thoroughly cooked eggs, with component-resolved diagnostics indicating sensitization to ovalbumin (Gal d2) but not ovomucoid (Gal d1).

CONCLUSION

Our study demonstrates a low frequency of FAs in adults yet highlights the seriousness of reactions like anaphylaxis. Hen's egg allergy was notably prevalent, underscoring the need for increased awareness and improved diagnostic strategies to effectively manage FAs in the adult population.

Exploring geographical variances in component-resolved diagnosis within the Asia-Pacific region

Component-resolved diagnostics (CRD) have revolutionized allergy diagnosis, offering enhanced accuracy and insights into allergen sensitization patterns. This review explores geographical variances in CRD for food and aeroallergens across the Asia-Pacific region. We examine the varying prevalence of allergic diseases and the utility of CRD in diagnosing common food allergies, including peanut, shellfish, fish, wheat, and fruits. Notable differences in serum-specific (sp)IgE sensitization patterns and the clinical relevance of particular allergen components are observed between populations in Asian countries and those in Europe and the United States. For food allergies, the literature reports significant differences in allergen components and their diagnostic utility across various countries. Peanut allergy diagnostics, particularly Ara h 2 spIgE, show varying sensitivity and specificity between Asian and Western populations. In shellfish allergy, emerging allergens beyond tropomyosin are gaining importance in the Asia-Pacific region. Fish and wheat allergies also demonstrate unique sensitization patterns, emphasizing the need for region-specific diagnostic approaches. Regarding aeroallergens, pollen sensitization profiles vary widely across the region, influenced by local flora and climate, to influence symptoms of pollen food allergy syndrome. House dust mite allergens remain a significant concern, with high sensitization rates to major components like Der p 1, Der p 2, and the emerging Der p 23. The cross-reactivity between house dust mite and shellfish allergens is particularly relevant in this region. These findings emphasize the need for region-specific CRD approaches, considering local allergen profiles and sensitization patterns. As the prevalence of allergic diseases continues to rise in the Asia-Pacific, further research into locally relevant allergens and their components is crucial for improving diagnosis, patient management, and targeted immunotherapy strategies in this diverse region.

Novel diagnostics in food allergy

Food allergy is increasing in prevalence, posing significant challenges for individuals and their families and adversely affecting their quality of life. Misdiagnosis can lead to unnecessary dietary and social limitations and increased food allergy risk, whereas failure to diagnose may result in life-threatening anaphylaxis. Therefore, a precise diagnosis is of the utmost importance; however, barriers exist at every stage of the diagnostic process. Diagnosis of food allergy relies on clinical history, IgE sensitization tests, and oral food challenge. Component testing and identification of optimal cutoffs have improved diagnostic accuracy. Nevertheless, many patients still require an oral food challenge, and better tests are needed to reduce this need. Novel ways of detecting biomarkers, such as the basophil activation test and peptide-specific IgE level, are transitioning into clinical practice. Future approaches may include the use of alternative biologic samples, novel laboratory technologies, and analytic tools (including artificial intelligence) to integrate test results and clinical information. Conscientious use of existing tests, access to tests with superior diagnostic accuracy, and combination of tests, can lead to improved precision of diagnosis of food allergy and timely introduction of tolerated foods into the diet. This review summarizes recent advances in novel approaches to food allergy diagnosis that can enhance clinical decision making both now and in the future.

Enzymatic treatment to decrease the allergenicity of Pru p 3 from peach

Pru p 3, a member of the lipid transfer protein family, is considered a major allergen from peach as it often induces serious allergic reactions in peach-allergic individuals. The high resistance of Pru p 3 to processing treatments and to digestion or enzymatic hydrolysis is probably the cause of the severity of this fruit allergy. The aim of this study was to determine the effect of treatment with a large number of proteases from different origins (vegetal, animal and microbial) on the degradation and allergenicity of Pru p 3. To perform this study, Pru p 3 was previously isolated using cation exchange chromatography and ultrafiltration, and the purified protein was incubated with proteases under different conditions. The results showed that only two of the fifteen proteases assayed were able to efficiently degrade the protein at acidic pH, as determined by SDS-PAGE. These two commercial acid proteases, derived from Aspergillus niger, decreased by more than 95% the immunoreactivity of Pru p 3 by ELISA using specific rabbit IgG, giving peptides lower than 3.2 kDa as determined by MALDI-TOF mass spectrometry. The hydrolysates obtained showed a greater than 70% decrease in reactivity of IgE compared to untreated Pru p 3 using three pools of sera from peach allergic individuals. Furthermore, when hydrolysates were tested by the prick test, in more than 90% of peach-allergic patients the average size of the wheal significantly decreased by between 72% and 85%. The results suggest that the acid protease from Aspergillus niger could be used to obtain novel hypoallergenic products more tolerable for peach-sensitive individuals.

The risk of anaphylaxis on holidays

PURPOSE OF REVIEW

The goal of this review is to summarize the potential causes of anaphylaxis in the different holiday contexts, providing practical suggestions aimed to mitigate the stress challenged by allergic patients because of unfamiliar situations.

RECENT FINDINGS

A regard was reserved to potential food triggers, particularly uncommon ones and typical of certain destinations, and to arthropods responsible for anaphylaxis.

SUMMARY

This review highlights the potential risk of anaphylaxis due to the unusual contexts more experienced during holidays (i.e., travels, outdoor activities and eating out). Moreover, it underlines the need for a further allergological education in these cases, in order to prepare allergic patients to avoid and manage undesired situations.

Malnutrition and Allergies: Tipping the Immune Balance towards Health

Malnutrition, which includes macro- and micronutrient deficiencies, is common in individuals with allergic dermatitis, food allergies, rhinitis, and asthma. Prolonged deficiencies of proteins, minerals, and vitamins promote Th2 inflammation, setting the stage for allergic sensitization. Consequently, malnutrition, which includes micronutrient deficiencies, fosters the development of allergies, while an adequate supply of micronutrients promotes immune cells with regulatory and tolerogenic phenotypes. As protein and micronutrient deficiencies mimic an infection, the body's innate response limits access to these nutrients by reducing their dietary absorption. This review highlights our current understanding of the physiological functions of allergenic proteins, iron, and vitamin A, particularly regarding their reduced bioavailability under inflamed conditions, necessitating different dietary approaches to improve their absorption. Additionally, the role of most allergens as nutrient binders and their involvement in nutritional immunity will be briefly summarized. Their ability to bind nutrients and their close association with immune cells can trigger exaggerated immune responses and allergies in individuals with deficiencies. However, in nutrient-rich conditions, these allergens can also provide nutrients to immune cells and promote health.

HLA variants and their association with IgE-Mediated banana allergy: A cross-sectional study

Background

Banana allergy is on the rise in tropical regions. Advances in genomics and candidate gene identification have increased interest in genetic factors in food allergies. However, the genetic basis of IgE-mediated banana allergy is underexplored.

Objective

To characterize HLA variants and their association with IgE-mediated banana allergy.

Methods

This cross-sectional study recruited banana-allergic adults, confirmed by allergology tests, with non-allergic individuals as controls. Genomic DNA extraction and sequencing BAM files for HLA typing were conducted. Allele frequency was calculated using the direct counting method, and odds ratio (OR) with 95 % confidence interval (CI) were determined. Fisher's exact or chi-square tests were used to assess associations with Bonferroni's correction for multiple tests. The allele frequency of the Thai population from The Allele Frequency Net Database was used to compute the allele enrichment ratio (ER).

Results

A total of 59 cases and 64 controls were recruited. HLA genotyping indicated potential associations of HLA-B*15:25 (OR 11.872; p-value 0.027), HLA-C*04:03 (OR 7.636; p-value 0.033), and HLA-DQB1*06:09 (OR 11.558; p-value 0.039) with banana allergy. However, after Bonferroni correction, none of these associations reached statistical significance. Comparing allele frequency with the general population from The Allele Frequency Net Database, our ER analysis revealed a higher prevalence in the banana allergy group for B*15:25 (ER 1.849), C*04:03 (ER 1.332), and DQB1*06:09 (ER 6.602) alleles.

Conclusions

This study provides initial genetic insights into banana allergy, suggesting potential links with specific HLA alleles. Despite 12 initially identifying alleles, none were statistically significant after multiple testing correction. Larger studies are needed to detect possible significant correlations.

Profiles of apple allergen components and its diagnostic value in Northern China

Background

Limited is known on the profiles of apple allergy in China.

Objective

To explore the clinical significance of apple allergen components in northern China.

Methods

This study recruited 40 participants and categorized into apple tolerance (n = 19) and allergy (n = 21) group. The latter was categorized into oral allergy symptoms (OAS, n = 14) and generalized symptoms (GS, n = 7). All participants underwent ImmunoCAP screening to assess sIgE levels of birch, apple, and their components.

Results

The sensitization rates were 90% for Bet v 1, 85% for Mal d 1, 35% for Bet v 2, and 20% for Mal d 3. The overall positive rate for apple allergens was 97.5%, with half demonstrating mono-sensitization to Mal d 1. Birch, Bet v 1 and Mal d 1 sIgE levels had consistent areas under the curve (AUC 0.747, p = 0.037; AUC 0.799, p = 0.012; AUC 0.902, p < 0.001 respectively) in diagnosing apple allergy. The optimal cut-off values were determined to be 22.85 kUA/L (63.6% sensitivity, 85.7% specificity), 6.84 kUA/L (81.8% sensitivity, 71.4% specificity) and 1.61 kUA/L (93.8% sensitivity, 75.0% specificity), respectively. No allergens or components demonstrated diagnostic value in distinguishing between OAS and GS. Mal d 3 sensitization was correlated with mugwort allergy and higher risk of peach, nuts or legumes generalized allergy.

Conclusion

Mal d 1 was major allergen and the best for diagnosing apple allergy. Mal d 3 does not necessarily indicate severe allergic reaction to apples in northern China but may indicate mugwort sensitization and an increased risk of peach, nuts or legumes allergy.

Evaluation of Allergic Reactions and Tolerance with Fruit and Vegetable Allergy in Children

INTRODUCTION

Despite the increasing prevalence of fruit and vegetable allergies in childhood over the past decades, the clinical course of reaction types and tolerance remain unclear. Our aim was to evaluate the clinical course, demographic characteristics, and tolerance rate of allergic reactions induced by fruits or vegetables.

METHODS

We conducted a retrospective, descriptive, cross-sectional study on patients who presented with suspected allergic reactions to fruit or vegetables. We used patient records to identify demographic data, skin prick test, prick-to-prick test, and oral food challenge test results and laboratory findings.

RESULTS

The study included 78 children with a median age of 61.5 months. Class 1 and 2 allergies were found in 65 and 13 cases, respectively. The most common allergens were potato (21.8%), banana (15.4%), peach (14.1%), and tomato (12.8%). Clinical symptoms included urticaria (75.6%), oral allergy syndrome (15.4%), angioedema (7.7%), and anaphylaxis (1.3%). Thirteen children achieved tolerance, while 61.7% did not. The median time to tolerance was 13.5 months after diagnosis, with a minimum of 9 months. Significant differences in reaction type, clinical presentation, pan-allergy to aeroallergens, and serum total IgE levels were found between the tolerant and non-tolerant groups (p = 0.006, 0.009, 0.005, and 0.001, respectively).

CONCLUSION

This is the first study to provide guidance on the tolerance rate and resolution time of fruit and vegetable allergies based on demographic and diagnostic parameters. Further research is needed to deepen our understanding of fruit and vegetable allergy.