[The prevalence of oral allergy syndrome: regarding a new classification]

Recently, the oral allergy syndrome (OAS) has been classified according to the foods that induce it: phenotype I, when it is caused only by plant-derived foods; phenotype II, when it is caused by foods of both animal and plant origin.

To determine the prevalence of OAS in late teenagers according to the new classification.

A cross-sectional study in which data from 1,992 teenagers, aged 15-18 year-old, was analyzed; the information was obtained through a structured questionnaire, where questions were asked about oral symptoms according to the type of food that had been ingested.

The overall prevalence of OAS was of 1.7% (95% CI = 1.2-2.4); for phenotype I, it was of 0.85% and, for phenotype II, it was of 0.85%. According to the phenotype, there was no difference by sex and personal history of atopic disease; instead, the onset time of the symptoms did show an association with the phenotype (p = 0.048). The frequency of skin and mucosal symptoms and respiratory ailments differed between the groups. Regarding gastrointestinal symptoms, diarrhea was markedly more frequent in phenotype II (p = 0.044).

Two phenotypes with OAS were clearly identified: the first one was associated exclusively to foods of plant origin, and the other was related to foods of both plant and animal origin.