Pollen food allergy syndrome (PFAS)

Pollen-food allergy syndrome (PFAS)

• is an immunoglobulin E-mediated immediate allergic reaction caused by cross-reactivity between pollen and the antigens of foods - such as fruits, vegetables, or nuts - in patients with pollen allergy
  
  
• is a common adverse reaction occurring few minutes after the consumption of vegetable foods in patients with pollen-induced seasonal allergic rhinoconjunctivitis (SAR) (2)
  • in Northern European countries
    • many patients with birch tree pollen sensitization develop PFAS that is induced by plant food, such as tree nuts and fruits, particularly those of the Rosaceae family
  • in Southern European countries
    • PFAS is mainly represented in patients polysensitized to various pollens
  • in Japan
    • sensitization to Japanese cedar is the main trigger of airborne allergy, and it's associated with PFAS due to fresh tomato in some cases
  • in Australian children
    • watermelon is the most common triggering food among children with grass pollen and birch allergy
      
      
• pathogenesis of PFAS
  • is linked to a respiratory allergy to pollens and subsequent cross-reactivity between pollens and homologous epitopes contained in plant-derived food proteins (class 2 food allergy) (2)
    • is a type I cross-reaction mediated by IgE antibodies between an aeroallergen and a plant-derived antigen (3)
      
      
• is often called oral allergy syndrome because symptoms appear mainly in the lips, mouth, and pharynx
  • clinically characterized most frequently by isolated oral and pharyngeal symptoms at immediate onset following food intake, which is called oral allergy syndrome (OAS) (2)
  • symptoms typically consist of localized oral symptoms such as numbness of the lip or mouth, itching, tingling and swelling of lips, tongue, palate and pharynx without systemic symptoms (3)
  • PFAS however is a more appropriate term because the symptoms appear around the mouth as well as in the gastrointestinal tract and respiratory organs (1)
  • symptoms of PFAS are generally restricted to the oropharyngeal mucosa and occur immediately, or in 5-10 min after consuming fresh fruits, vegetables, nuts, legumes and seeds (2)
    • oropharyngeal symptoms comprise:
      • labial and oropharyngeal pruritus,
      • paresthesia,
      • angioedema of the oral mucosa, lips, tongue, palate and pharynx,
      • itchy ears,
      • mucosal red patches and blisters and sensation of laryngeal tightness that may cause hoarseness (OAS)
    • symptoms typically last for a few minutes to half an hour
    • systemic reactions have been reported in 2-10% of cases
      
      
• pollen sensitization is uncommon in young children, and PFAS occurs more frequently in older children, adolescents, and adults (1)

Reference:

• Jeon YH. Pollen-food allergy syndrome in children. Clin Exp Pediatr. 2020 Dec;63(12):463-468. doi: 10.3345/cep.2019.00780. Epub 2020 May 14. PMID: 32403897; PMCID: PMC7738766.
• Mastrorilli C, Cardinale F, Giannetti A, Caffarelli C. Pollen-Food Allergy Syndrome: A not so Rare Disease in Childhood. Medicina (Kaunas). 2019 Sep 26;55(10):641. doi: 10.3390/medicina55100641. PMID: 31561411; PMCID: PMC6843262.
• Kar Kurt O et al [Pollen food allergy syndrome]. Tuberkuloz ve Toraks. 2017 Jun;65(2):138-145. DOI: 10.5578/tt.32167. PMID: 28990893.