Cross-Reactivity and Seasonal Allergies

Often, avoiding specific environmental triggers is not enough to lessen allergy symptoms.


Dominique Vanier
Dominique Vanier

24 May 2017


Since many allergens contain proteins that are similar to various proteins found in food, individuals who are allergic to birch pollen, for example, may also experience allergy symptoms when eating kiwis, apples, carrots, celery, tomatoes, and curry – foods whose proteins look molecularly similar to those found in birch pollen.

Known as “cross-reactivity,” the proteins found in these fruits and vegetables confuse the immune system and can cause an allergic reaction or add to existing symptoms during allergy season. In adults, up to 60 percent of food allergy reactions may in fact be due to cross-reactivity between food and pollen.

Oral allergy syndrome (OAS) is the term given to cross-reactivity between food and pollen that occurs when raw fruits and vegetables come in contact with the mouth. This frequently leads to itchiness or swelling of the mouth, face, lips, tongue and/or throat, and potentially digestive distress. These allergy symptoms may appear immediately after ingesting the offending foods, or may be delayed in onset.

Helpful tips

While it may be a nuisance that oral allergy syndrome can occur all year round, there are some lifestyle and diet modifications that can help alleviate symptoms and lower frustration levels. Below are some helpful tips that may clear your sinuses and dry your watery eyes:

  • Avoid triggers. Though it may be impossible to completely avoid all environmental triggers, some measures are in your control – such as going for a run on the treadmill indoors rather than outside during allergy season.
  • Become educated. If you continue to experience allergic reactions after removing all known triggers, investigate whether you may be suffering from oral allergy syndrome and experiment with a diet that eliminates the corresponding fruits and vegetables that cause cross-reactivity.
  • Keep your home allergen-free. Taking measures to rid your home of allergens, especially during allergy season, may lessen your symptoms. Removing your shoes at the door and frequently washing your hair and clothes can help reduce the spread of pollen through the home and bedroom.
  • Dehumidify the home. Since mould grows quickly in heat and humidity, consider purchasing a de-humidifier if you have a mould allergy – which will add more stress to the immune system if you also suffer from seasonal allergies.
  • Replace filters in the furnace. Air filtration is recommended as a measure of environmental control for individuals who suffer from allergic respiratory diseases. Replacing air filters and air ducts can help minimize exposure to allergens in the home (and pollen that has made its way in).
  • Be proactive. Take a preventative approach to managing your seasonal allergies. Allergy Relief can provide symptomatic relief for sneezing attacks and nasal congestion when it is taken for one month in advance of the start of allergy season.
  • Work with your healthcare practitioner. It is important to work with your primary healthcare provider who will advise you on appropriate medical treatment and monitor your symptoms.