Walnut Tree
Allergy Facts, Symptoms, and Treatment

Producing an edible fruit, walnuts are deciduous trees constituting the genus Juglans. Distributed across North and South America, southern Europe, Asia, and the West Indies, various walnut tree species are reported to be moderately allergenic.1,2 Where nut orchards are common, walnut pollen is reported to be a serious cause of pollinosis (aka hay fever and allergic rhinitis).2 Walnut trees are wind pollinated.3

Where are walnut trees found?

Walnuts trees are native to southern Europe, Asia, the West Indies, and North and South America.1

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Are there other allergens I could be sensitized to?*

Many patients with walnut tree allergy can experience symptoms when exposed to other allergens such as tree, weed, or grass pollens, making it difficult to determine which pollen is causing the symptoms, especially when pollen seasons are overlapping. This is called cross-reactivity and occurs when your body's immune system identifies the proteins, or components, in different substances as being structurally similar or biologically related, thus triggering a response.8 Other respiratory allergens that may cause reactions associated with walnut tree pollen allergy include pecan, hickory, and limited other tree, weed, and grass pollens.9

*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.

How do I manage my allergy?

The management of allergic rhinitis includes avoidance of relevant allergens, symptomatic treatment, and allergen immunotherapy.5-7

  • Check local pollen counts daily and limit time outside when tree-pollen counts are high. Rain helps clear pollen from the air, so the best time to go outside is after a good rain.
  • Delegate outdoor chores whenever possible and wear a pollen mask if you must do outside tasks. 
  • Keep windows closed and use air conditioning instead.
  • Wash bedding at least once a week in hot, soapy water.
  • Wash your clothes after outdoor activities and dry all clothes in a dryer as opposed to line drying outdoors.
  • Bathe and wash your hair every day before bedtime to keep pollen out of your bed.
  • Wipe off any pets to remove pollen before letting them into your home.
  • Ensure everyone removes their shoes before entering your home.
  • Use certified asthma and allergy air filters.
  • Pharmacological treatment, including antihistamines, corticosteroids, decongestants, and saline douches.
  • Allergen immunotherapy as directed by your healthcare provider.

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Walnut Tree Allergen Facts, Symptoms, & Treatment

Common Symptoms

Walnut tree allergy symptoms can be similar to many other pollen allergies and may include:4,5

  • Sneezing
  • Nasal congestion
  • Runny nose
  • Watery eyes
  • Itchy throat and eyes
  • Wheezing

If you're sensitized to walnut trees and have asthma, tree pollen may trigger or worsen asthma symptoms, such as coughing and wheezing.4,5

How do I know if I'm allergic?*

Together with your symptom history, skin-prick testing or specific IgE blood testing can help determine if you are sensitized to a particular allergen. If you are diagnosed with an allergy, your healthcare provider will work with you to create a management plan.

*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.

Pollen Season

While tree pollen is common in the spring, walnut tree pollen is shed abundantly between April and June in parts of the Northern Hemisphere.2,4

  1. Encyclopedia Britannica [Internet]. Chicago: Encyclopedia Britannica Inc.; 2019 May 17. Available from: https://www.britannica.com/plant/walnut-tree-and-nut.
  2. Pollen.com [Internet]. Plymouth Meeting, PA: IQVIA Inc.; 2020. Available from: https://www.pollen.com/research/genus/juglans.
  3. Snyder M. Northern Woodlands [Internet]. Lyme, NH: Northern Woodlands; 2009 Apr 20. Available from: https://northernwoodlands.org/articles/article/why_are_some_trees_pollinated_by_wind_and_some_by_insects.
  4. American College of Allergy, Asthma & Immunology [Internet]. Arlington Heights, IL: American College of Allergy, Asthma & Immunology; 2014 [2018 Apr 23]. Available from: https://acaai.org/allergies/types/pollen-allergy.
  5. Roberts, Graham & Xatzipsalti, M & Borrego, Luis & Custovic, Adnan & Halken, Susanne & Hellings, Peter & Papadopoulos, Nikolaos & Rotiroti, G & Scadding, Glenis & Timmermans, Frans & Valovirta, Erkka. (2013). Paediatric rhinitis: Position paper of the European Academy of Allergy and Clinical Immunology. Allergy. 68. 10.1111/all.12235.
  6. Asthma and Allergy Foundation of America [Internet]. Arlington, VA: Asthma and Allergy Foundation of America; 2019 Apr 9. Available from: https://community.aafa.org/blog/tips-for-preventing-allergic-reactions-to-tree-and-grass-pollen.
  7. Mayo Clinic [Internet]. Rochester, MN; Mayo Foundation for Medical Education and Research; 2020 Apr 16. Available from: https://www.mayoclinic.org/diseases-conditions/hay-fever/in-depth/seasonal-allergies/art-20048343.
  8. Matricardi PM, Kleine-Tebbe J, Hoffmann HJ, Valenta R, Hilger C, Hofmaier S, Aalberse RC, Agache I, Asero R, Ballmer-Weber B, Barber D, Beyer K, Biedermann T, Bilò MB, Blank S, Bohle B, Bosshard PP, Breiteneder H, Brough HA, Caraballo L, Caubet JC, Crameri R, Davies JM, Douladiris N, Ebisawa M, EIgenmann PA, Fernandez-Rivas M, Ferreira F, Gadermaier G, Glatz M, Hamilton RG, Hawranek T, Hellings P, Hoffmann-Sommergruber K, Jakob T, Jappe U, Jutel M, Kamath SD, Knol EF, Korosec P, Kuehn A, Lack G, Lopata AL, Mäkelä M, Morisset M, Niederberger V, Nowak-W?grzyn AH, Papadopoulos NG, Pastorello EA, Pauli G, Platts-Mills T, Posa D, Poulsen LK, Raulf M, Sastre J, Scala E, Schmid JM, Schmid-Grendelmeier P, van Hage M, van Ree R, Vieths S, Weber R, Wickman M, Muraro A, Ollert M. EAACI Molecular Allergology User's Guide. Pediatr Allergy Immunol. 2016 May;27 Suppl 23:1-250. doi: 10.1111/pai.12563. PMID: 27288833.
  9. Weber RW. Patterns of pollen cross-allergenicity. J Allergy Clin Immunol 2003;112:229-39.
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