Reactions after natural and artificial food additives in urticaria: should we pretend they do not exist?

Introduction
Hypersensitivity to food additives is still under investigation.

Aim
To evaluate the incidence of reactions to food additives and their clinical significance in urticaria patients and suspected hypersensitivity to them.

Material and methods
The study included patients hospitalized at the Department of Allergology and Pneumology of the Medical University of Gdansk in 2017–2019 with suspected hypersensitivity to food additives. The following substances were selected for the study: sodium metabisulfite, carmine, annatto, monosodium glutamate, sodium benzoate, and a mixture of azo dyes. A standardized questionnaire, skin prick tests, patch tests, and sIgE level evaluation for carmine were used in the diagnostic procedure. All the patients with positive skin testing, elevated sIgE level or suspected hypersensitivity for food additives were qualified for the single-blind placebo-controlled oral challenge.

Results
One hundred and ten patients were enrolled in the study. Out of 171 challenges carried out, 25 were positive in 22 subjects.

Conclusions
Food additives can exacerbate and induce hypersensitivity reactions in IgE- and non-IgE-dependent mechanisms.