Tree nut allergy

Natural History of Hazelnut Allergy and Current Approach to Its Diagnosis and Treatment

Hazelnut allergy is the most prevalent type of nut allergy in Europe, with symptoms that can range from mild, such as hives and itching, to severe, such as anaphylaxis, particularly in patients who are sensitized to highly stable allergens, such as storage proteins. Compared to other types of food allergies, allergies to tree nuts, including hazelnuts, tend to persist throughout life. Although symptoms can appear in early childhood, they often continue into adulthood, with a minority of cases improving during adolescence. Currently, there is no curative treatment available for hazelnut allergy, and patients must adhere to a restrictive diet and carry autoinjective epinephrine. However, oral allergen immunotherapy (AIT) is a promising treatment option. Patients can be categorized based on their risk for severe reactions using various clinical, in vivo, and in vitro tests, including component-resolved diagnosis and oral food challenge. This review aims to provide an overview of the current knowledge of the natural history of hazelnut allergy and new approaches for its diagnosis and management.

Prevalence of nut allergen sensitization among children in central Poland

Introduction

The diagnostics of plant-derived food allergy may be challenging. However, the recognition of sensitization patterns in defined populations, especially in children, is clinically relevant as it enables the use of secondary prophylaxis to prevent life-threatening complications.

Aim

To investigate the rates and sensitization patterns to nut allergens in children from central Poland.

Material and methods

The retrospective assessment concerned data of 598 children diagnosed in a single centre due to suspected food allergy. The analysis included the results of component-based multiparametric assay Allergy Explorer2 (ALEX2).

Results

The sensitization to particular nut allergens varied among patients, depending on their age and nut type. The sensitization to any nut was found in 67% of children, whereas sensitization to hazelnut and peanut was the most common (56% and 55% of all children, respectively). Hazelnut sensitization was predominant in every age, and its prevalence increased with age, while peanut sensitization was detected in more than half of individuals from all groups, except for teenagers (44% of cases). Among hazelnut molecules sensitization to Cor a 1.04 was the most prevalent (74% of sensitized children), and for peanut allergens - Ara h 1 (65% of sensitized patients). The simultaneous sensitization to hazelnut, peanut and walnut (two or all of them) was found in almost half of the entire group.

Conclusions

Component-based diagnostics enables differentiation between primary and cross-reactive sensitization to nut allergens and detects co-sensitization. The clinical relevance of the latter observation is remarkable as co-sensitization increases the risk of life-threatening reactions even in trace nut contamination.