Environmental Allergies and Pollen Food Syndrome (PFS)

Abstract

The occurrence of pollen food syndrome (PFS) is increasing in the pediatric population. Investigators in Europe, Australia, and Mexico have documented the prevalence of PFS as high as 10–24% and related the increase to the rise in seasonal allergic rhinitis worldwide. Tree pollen allergy patients, especially birch pollen allergic patients, are the most likely to develop PFS. Patients experience PFS when eating fresh fruits, raw vegetables, nuts, and spices. Symptoms begin when fresh fruit contacts the oral mucosa producing itching, tingling, and swelling of the mouth, tongue, and throat. The symptoms usually resolve quickly with swallowing. PFS is a class 2 food allergy caused by cross-reacting antibodies that have developed via the respiratory tract in response to pollen allergens, in contrast to class 1 food allergy, where antigen sensitization to milk, egg, soy, wheat, peanut, or tree nuts occurs in the gastrointestinal tract. It is important to distinguish between the clinical symptoms of PFS and food allergy because PFS is limited to the oral mucosa and infrequently causes systemic symptoms leading to anaphylaxis. Standard skin testing with commercial as well as IgE immunoassay testing for foods responsible for PFS is sometimes unhelpful, and clinical history is very important in interpreting results. It is hoped that component-resolved diagnostics (CRD), as an alternative to or in combination with traditional testing, can help identify the significant molecular antigens associated with clinical symptoms and lead to improved diagnosis and effective immunotherapy.