Acute allergic reactions to food are often IgE mediated. Symptoms vary in severity; from mild oral itching to anaphylactic reactions. Where birch pollen allergy is endemic, mild allergic reactions from e.g. fresh fruits and nuts are most likely caused by cross reactivity between pollen and plants (cross reactions). These mild symptoms, if caused by cross reactivity, do not progress to more severe symptoms, in contrast to »true« food allergy. However, making this distinction is a delicate task, since more severe reactions also often start with mild oral symptoms. Also conventional allergy tests, such as skin-prick test and blood test to detect IgE-antibodies (IgE-ab) to foods, discriminate poorly between cross reactions and true allergy. Component resolved diagnostics, i.e. analysis of IgE-ab to specific proteins in an allergen and CD-sens (Basophil allergen threshold sensitivity), can differentiate pollen-related cross reactions from true allergic reactions that may cause anaphylaxis. There is no widely accepted or evidence based treatment for food allergy, but reports from several studies have been published and many are in progress, where oral immunotherapy probably is the most promising form of treatment.