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When Pollen Meets Food Allergens: Pollen-Food Syndrome (PFS) -Part II

Updated: Jan 9

HK BioTek Intern

Diagnosing PFS

Although PFS symptoms usually subside quickly once the contact between the food and oral cavities is removed, they may also manifest in a more severe manner. The proper diagnosis is crucial to determine such possibility. Therefore, if you have repeatedly experienced PFS symptoms after consuming raw fruits and vegetables, please see a general practitioner (GP) or your family doctor as soon as possible to receive medical advice.


Some GPs may have a clear understanding of allergy, but due to the cross-reactivity between allergens, diagnosing PFS is somewhat complicated. Your GP will most likely refer you to an allergist if your PFS symptoms are severe, since an allergist is professionally trained to find the source of your symptoms and help you ease the discomfort.


There is no standard procedure for diagnosing PFS, but the common practice is that the allergist first discusses with the patient about his or her PFS symptoms and records his or her clinical history, then conducts a skin prick test mostly to the birch pollen, oral food challenge with raw fruits or vegetables, and a blood test to detect the blood level of IgE antibodies responsible for allergic reactions to birch pollen. Pollen allergy and PFS are mainly reflected from the positive results for many plant foods in the skin prick test.


Managing PFS

Many who have PFS usually display mild allergy symptoms. If you are one of the lucky ones, you can still enjoy eating without making big changes to your usual dietary habits:

  • Try cooked (e.g., baked, microwaved) or canned versions of the raw foods you are allergic to.Heating and processing breaks down the heat- and digestive enzyme-sensitive proteins responsible for the PFS symptoms

  • If foods that have caused allergic reactions cannot be cooked (e.g., melons), you should avoid eating them

  • Avoid eating the allergy-causing food in raw state, especially during pollen season, as PFS symptoms worsen during this period

  • Deskin foods if applicable, as the offending protein is often concentrated in the skin

  • Unfortunately, if you fall under the “more severe” category, more stringent dietary restrictions and additional measures may apply:

  • If you have experienced severe PFS symptoms after eating nuts, avoid eating any type of nuts or any (potentially) nut-containing products, even in in cooked form, is recommended. Since nut proteins cannot be degraded by heat or during processing

  • If you have experienced PFS symptoms to a wider range of fresh fruits and raw vegetables, consult a registered dietitian to avoid being deprived of important nutrients such as vitamins, minerals and fibre

  • If you have suffered severe allergic reactions, always carry the epinephrine auto-injector that your allergist may have prescribed you

  • If you are affected by major risk factors of severe allergic reactions (e.g., asthma), minimise these risk factors as best as you can

(This content is informative only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment.)


References:

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