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Clinical manifestations and diagnosis of oral allergy syndrome (pollen-food allergy syndrome)

Anna Nowak-Węgrzyn, MD
Section Editor
Scott H Sicherer, MD, FAAAAI
Deputy Editor
Anna M Feldweg, MD


The oral allergy syndrome (OAS) (pollen-food allergy syndrome [PFAS or PFS]) is a relatively common form of food allergy, particularly in adults. It occurs in people who have pollen allergy, although not all patients have obvious hay fever or seasonal allergy symptoms. Patients typically report itching and/or mild swelling of the mouth and throat immediately following ingestion of certain uncooked fruits (including nuts) or raw vegetables. The symptoms result from contact urticaria in the oropharynx caused by pollen-related proteins in these foods. Only a small proportion of affected individuals experience systemic allergic reactions, although the disorder must be differentiated from more serious forms of food allergy.

This topic reviews the epidemiology, clinical manifestations, and diagnosis of OAS and describes associations between specific pollens and foods. The pathogenesis, management, and prognosis of OAS are presented separately. (See "Pathogenesis of oral allergy syndrome (pollen-food allergy syndrome)" and "Management and prognosis of oral allergy syndrome (pollen-food allergy syndrome)".)

Terminology — At least two terms are used to describe this type of allergy:

Oral allergy syndrome — The term "oral allergy syndrome" (OAS) is widely recognized. However, it has been imprecisely applied in the literature to describe oropharyngeal reactions due to a variety of nonplant foods as well as both oropharyngeal and systemic symptoms due to plant foods in subjects with pollen allergy. This imprecision has led to considerable confusion. In this review, OAS is used to describe reactions caused by pollen-related foods that are limited to the oropharynx.

Pollen-food allergy syndrome — The terms "pollen-food allergy syndrome," "pollen-food syndrome," and "pollen-associated food allergy syndrome" (abbreviated PFAS or PFS) are increasingly used instead of OAS, both to emphasize the pathogenesis of these reactions and to describe the full range of oropharyngeal and systemic symptoms that can occur in response to pollen-related foods [1-3]. In this review, PFS is the preferred term for the entire spectrum of reactions caused by pollen-related plant foods.

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Literature review current through: Nov 2017. | This topic last updated: Oct 12, 2017.
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