PollenFoodSyndrom

PollenFoodSyndrom, also known as pollen-food allergy syndrome or oral allergy syndrome (OAS), is a form of IgE-mediated cross-reactive food allergy that occurs in people with pollen allergies. It results from immune recognition of proteins in certain plant foods that resemble pollen allergens.

The mechanism involves IgE antibodies raised against pollen recognizing similar epitopes in foods such as fruits, vegetables, and nuts. When these raw foods are eaten, the immune system can trigger localized allergic reactions in the mouth and throat. Cooking often denatures the offending proteins, reducing or eliminating symptoms. Common triggers include raw apples and pears with birch pollen, stone fruits like peaches and plums, nectarines, kiwifruit, carrots, celery, hazelnuts, and almonds.

Symptoms are typically immediate and localized to the mouth, lips, tongue, and throat, presenting as itching, tingling, or swelling after consumption of the raw food. Most reactions are mild, but some individuals may experience nasal symptoms or, rarely, more extensive reactions.

Diagnosis relies on clinical history and supporting allergy tests. Skin prick testing or serum-specific IgE tests to both pollens and suspected foods can help confirm cross-reactivity. An oral food challenge may be used in uncertain cases to determine tolerance to specific foods.

Management focuses on avoidance of the raw trigger foods or choosing tolerated forms. Many patients can eat cooked or processed versions of the foods without symptoms, as heating reduces the allergenic proteins. Patients should discuss a plan with an allergist, which may include antihistamines for mild symptoms and an emergency action plan for rare severe reactions.