Background: Allergic rhinitis (AR) is highly prevalent worldwide and is rarely an isolated condition. Sensitization to inhalant pollen allergens can lead to unexpected clinical consequences beyond the respiratory tract, one of which is pollen-food allergy syndrome (PFAS), also known as oral allergy syndrome. Patients with AR sensitized to birch, ragweed, or grass pollen frequently develop hypersensitivity reactions to a wide range of plant-derived foods.

Objective: This review aims to summarize current knowledge on the epidemiology, pathogenesis, clinical manifestations, diagnosis, and management of patients with comorbid allergic rhinitis and pollen-food allergy syndrome.

Methods: A narrative review of the literature was conducted, focusing on recent advances in molecular allergology and clinical management of PFAS.

Results: PFAS occurs in 23–76% of patients with AR, depending on geographic region and pollen sensitization profile. The underlying mechanism is cross-reactivity between heat-labile pollen proteins (e.g., Bet v 1, profilins) and homologous proteins in fresh fruits, vegetables, and nuts. Clinically, PFAS typically presents as oral allergy syndrome (itching, burning, and angioedema of the lips, tongue, and palate) occurring within minutes of consuming raw trigger foods. Importantly, most cross-reactive allergens are heat-labile, allowing patients to tolerate cooked or processed forms of the same foods. Although symptoms are usually mild and confined to the oropharynx, systemic reactions, including anaphylaxis, occur in 1.7–8.7% of cases. Diagnosis is based on a thorough history, skin prick testing, specific IgE measurement, and component-resolved diagnostics to differentiate labile from stable allergens. Management includes control of underlying AR with intranasal corticosteroids and antihistamines, dietary avoidance of raw trigger foods, patient education on recognizing systemic symptoms, and, in selected cases, allergen immunotherapy (AIT) directed against the primary pollen sensitization.

Conclusion: PFAS is a common but underdiagnosed comorbidity of allergic rhinitis. Clinicians should routinely screen AR patients for food-induced oral symptoms. A molecular approach to diagnosis enables accurate risk stratification and personalized dietary advice. Allergen immunotherapy for pollen AR may reduce PFAS symptoms, although further studies are needed.

Allergic rhinitis; pollen-food allergy syndrome; oral allergy syndrome; Bet v 1; cross-reactivity; pollen; food allergy; component-resolved diagnostics

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