Oral allergy syndrome, also known as a PFS, is usually associated with adults and characterised by mild transient oropharyngeal symptoms. The purpose of this review is to determine whether systemic or anaphylactic reactions do occur and, if so, who is affected and what are the triggers.

An increasing number of studies demonstrate that PFS occurs in all age groups, and a significant number of affected adults do experience systemic and anaphylactic reactions. The upsurge in adopting vegan lifestyles, increased consumption of fruits and vegetables, including smoothies and juices, and use of plant foods in nutritional or body-building supplements could exacerbate this. Researchers may also involve changes in pollen and pollution levels, cofactors and sensitisation to other plant food allergens.

The study concluded that PFS would continue to experience mild symptoms. All individuals should be advised appropriately regarding the dangers of concentrated or unusual forms of plant food allergens such as smoothies, juices, soy/nut milk and nutritional supplements. Further, well-characterised studies are needed to determine risk factors for severe reactions and sensitisation patterns to pollens and plant food allergens.

Reference: https://journals.lww.com/co-allergy/Abstract/2020/10000/Can_patients_with_oral_allergy_syndrome_be_at_risk.7.aspx