Pecan and Hickory Trees
Allergy Facts, Symptoms, and Treatment

The Carya genus, aka hickory, is split into two groups of four species each: pecan hickory and true hickory. The former includes pignut hickory, shellbark hickory, shagbark hickory, and mockernut hickory. The latter offers water hickory, bitternut hickory, pecan, and nutmeg hickory.1 True hickory and pecan hickory trees are native to North America and Asia, but pecan trees (Carya illinoinensis) have been introduced to many countries.2,3 While hickory trees cause pollinosis (aka hay fever and allergic rhinitis) where the trees are abundant, pecans are reported to cause severe pollinosis. Both species are wind pollinated in the spring.4

Where are pecan and hickory trees found?

Both hickory and pecan trees are native to North America, but pecan trees have been introduced into many countries and are cultivated in Australia and South Africa.2,3

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Are there other allergens I could be sensitized to?*

Many patients with pecan and hickory 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.9 Other respiratory allergens that may cause reactions associated with pecan hickory pollen allergy include walnut trees and limited other tree, weed, and grass pollens.10

*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.6-8

  • 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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Pecan and Hickory Tree Allergen Facts, Symptoms, and Treatment

Common Symptoms

Pecan hickory tree allergy symptoms can be similar to many other pollen allergies and may include:5,6

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

If you're sensitized to pecan hickory trees and have asthma, tree pollen may trigger or worsen asthma symptoms, such as coughing and wheezing.5,6

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

Tree pollen is common in the spring.5

  1. Hardwood Floors [Internet]. Chesterfield, MO: National Wood Floor Association; 2018 Jan 17. Available from: https://hardwoodfloorsmag.com/2018/01/17/species-specs-hickorypecan.   
  2. Encyclopedia Britannica [Internet]. Chicago: Encyclopedia Britannica Inc.; 2016 Jan 6. Available from: https://www.britannica.com/plant/hickory-plant.
  3. Britannica [Internet]. Chicago: Encyclopedia Britannica Inc.; 2020 Apr 23. Available from: https://www.britannica.com/plant/pecan.
  4. Pollen.com [Internet]. Plymouth Meeting, PA: IQVIA Inc.; 2020. Available from: https://www.pollen.com/research/genus/carya.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. Weber RW. Patterns of pollen cross-allergenicity. J Allergy Clin Immunol 2003;112:229-39.
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