Low-allergenicity landscaping plant selection criteria for patients with pollen-related allergies

Patients with pollen-related allergic rhinoconjunctivitis or asthma and landscapers sometimes enquire about modifying outdoor environments to choose plants that are less likely to trigger symptoms. However, there are only few information sources available to help them identify allergenic plants and strategies to avoid personal exposure to them

Now, the Landscape Allergen Working Group of the American Academy of Allergy, Asthma and Immunology has created a guide, which for the first time lists plants of low allergenic potential and also provides general guidance on creating a low-allergenic landscape.

In general, trees, shrubs, and flowering plants with heavier versus lighter pollen are less allergenic, because heavier pollen is transported by insects rather than traveling through the air.

Published in the Journal of Allergy and Clinical Immunology: In Practice, the Working Group says that to avoid selecting plant species that could exacerbate seasonal allergies in individuals sensitized to them, the following selection criteria/guidelines should be considered during the design stages of a low-allergenic landscape:

·         Eliminate existing anemophilous species from your landscape if possible. Reduce grass pollen exposure and consider placement of shrubs or hardscaping.

·         Grass allergens may also become aerosolized in the absence of pollen with mowing, in combination or not with rainfall episodes.

·         Select a broad diversity of entomophilous, low-allergen producing species with little seasonal pollen production

·         Ensure that selected species do not cross-react with other characterized allergenic plant species to the best possible extent

To minimize exposure to biologic hazards, precautionary steps should be taken:

·         Wear protective clothing and equipment including long-sleeved shirts, long pants, gloves, and head and eye protection.

·         Apply insect repellent to prevent insect exposure and stings. Wear respiratory protection during disturbance activities such as digging soil, distributing mulch or compost, and mowing.

·         Carry self-injectable epinephrine for those susceptible to anaphylaxis following an insect sting.

·         Be aware of the season and potential exposure to pollen from neighboring areas.

·         Remove poison ivy (Toxicodendron radicans) or other plants identified to cause skin injuries and toxic reactions.

·         Landscaping employers should educate workers about pollen exposure and other biological hazards

“Although a completely allergy-free garden space outdoors is unrealistic, a reduced allergen or low-allergen landscape is feasible to design using the information and principles described”

(Source: Green BJ, Levetin E, Horner WE, et al. Landscape plant selection criteria for the allergic patient. J Allergy Clin Immunol Pract. 2018 Nov-Dec;6(6):1869-1876).

Dr KK Aggarwal

Padma Shri Awardee

President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Immediate Past National President IMA