Allergies to House Plants

By A Reis

Having ornamental plants is a popular choice to add colour and variety to your house or work place, but for some people just being in close proximity to plants is enough to trigger an allergic reaction.

Unfortunately, this is an area poorly researched and, in many cases, the actual allergen has not been identified yet. Most studies concentrate on occupational allergy, such as in gardeners, greenhouse workers and florists, but with the widespread use of plants in many public places, the exposure to allergens reaches many more.

Do plants prevent or cause allergies?

The answer may be both, depending on the allergy.

In addition to their decorative aspect, in 1989 NASA published a study that demonstrated that plants are capable of a much more important function than just their ornamental status. Certain plants can eliminate toxins present in the air, which make them exceptional air cleaners providing a much better atmosphere inside the house.

It was shown that plants absorb these substances through the leaves, as well as releasing moisture which reduces airborne toxins. This included pet dander and dust mites, as well as many other allergens. The study suggested the use of such plants as an inexpensive means of providing clean air indoors, particularly public places.

If you suffer from allergies, after reading this report, you would think that having plants in your house can potentially reduce the incidence of allergens and eliminate any symptoms. This is not the full story however, as many plants operate at the other end of the scale by triggering an allergic reaction, making life very difficult for those that have to cope with this condition.

If you start experiencing certain symptoms connected with your allergy suddenly after acquiring a new plant, unfortunately it may mean a plant allergen is the culprit.

Plant allergens

There are hundreds of different plant allergens that can cause a reaction, either by contact or inhalation. It is estimated that over 500 substances can cause such reaction from one plant family alone. These allergens vary immensely in their composition and diagnosis is sometimes difficult due to lack of tests specific for each one. In addition, exposure to more than one allergen simultaneously further complicates diagnosis.

Traditionally, classification of allergens is done based on botanical criteria of the correspondent plant, but this does not allow doctors to predict cross-reactivity to advise patients about what other plants have the same allergen and therefore should be avoided. Recently however, a classification based on the allergen’s chemical structure has been proposed which, if accepted, would facilitate finding identical allergens present in different plants but likely to cause the same reaction.

Most common plants allergens

According to scientific research and medical cases, ornamental plants most likely to trigger an allergic reaction include:

•       Chrysanthenum (Compositae family)

•      Tulips, hyacinths, lilies, crocuses (Liliaceae family)

•      Roses (Rosaceae family)

•      Weeping fig (Moraceae family)

•      Primulas (Primulaceae family)

•      Stephanotis floribunda (Apocynaceae family)

•      Spider plant and snake plant (Asparagaceae family)

•      Cymbidium and oncidium orchids (Orchydaceae family)

•      Marigold, dahlia and sneezeweed (Asteraceae family)

•      Tradescantia (Commelinaceae family)

•      Ginkgo (Ginkgoaceae family)

•      Silk oak (Proteaceae family)

What are the symptoms caused by plant allergens?

Obviously, symptoms depend on the way you get into contact with the allergen. You can either enter in direct contact with the allergen by touching the plant, which will cause various skin conditions; or indirectly, by inhaling airborne allergens, which will cause respiratory problems.

Direct contact with allergen causes skin reactions

Some plants secrete liquid from the fruit, leaves and stem, which can be potentially trigger an allergic reaction. If you touch the offending plants, your skin gets in contact with these substances and may cause itching, eczema, skin lesions, contact dermatitis, urticaria or even photodermatosis. In extreme cases, it may even result in swelling in the face, usually around the eyes or mouth (angiooedema) or anaphylatic shock.

Examples of plants that can cause a skin reaction include chrysanthemum, orchids, marigold and weeping ficus.

Indirect contact with allergen causes respiratory reactions

Plants can cause allergic reactions by other means other than just by contact. Inhaling airborne allergens can result in runny nose and itchy eyes (rhinoconjuntivitis) and allergic rhinitis, as well as lung inflammation, dyspneia or even asthma.

This type of allergy can be difficult to diagnose, as contact is not necessary and it may take some time for enough allergens to accumulate in the air to cause a reaction. Potentially, any ornamental plants that produce large amounts of pollen can cause an allergic reaction, but pollen is not the only airborne allergen.

How to avoid or reduce plant allergies?

•      Chose plants with flowers with little pollen and short stamens

•      Keep plants at floor level, to reduce area contaminated with potential allergens

•      Add one plant at a time to your house, to ensure that no allergies develop

•      Chose plants with smooth leaves, as fuzzy leaves can trap allergens easily

•      Examples of low allergy plants include cactus, begonia, nasturtium, peperomia and croton

•      Ensure your plants are always clear of any dust which can harbour airborne allergens

•      Spray the leaves with water to reduce the risk of airborne allergens

Conclusion

In conclusion, mostly due to lack of adequate testing, allergies caused by common house plants tend to be misdiagnosed and misunderstood. However, this can cause from mild skin irritation to serious allergic conditions that require medical attention. Further research is required to identify the chemical nature and mechanism of action of many still unknown allergens, which will help in developing new tests to facilitate diagnosis. Furthermore, a better understanding of allergens and their chemical structure would permit doctors to advise their patients about what other plants to avoid to reduce the incidence of allergic reactions.

10 Comments »

I will keep this article in mind as my sister gets sever allergies. I will try your suggestions by first presenting her with some nasturtium and she how she goes. Wish me luck

June 8th, 2014 | 8:35 pm
Tim Woodruff:

I recommend the OPALS(TM) (Ogren Plant Allergy Scale), which rates 5,000 plants from 1 (low) to 10 (you don’t want this in your life). Information can be found at http://www.allergyfree-gardening.com and the full list is published in “The Allergy-Fighting Garden” by Tom Ogren. The focus is on outdoor plants, but the information can easily be applied to houseplant and office plant choices.

April 17th, 2015 | 6:06 pm

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April 15th, 2016 | 12:49 pm

Hi there I have 3 indoor plants name : snake plant
Dracaena Janet and Dracaena asst or lemon lime
Sometimes I have touched the leves to clean them of the dust ” I don’t know if this plants can give me a skin allergic reaction? It’s been a while
Since I have them though but for this reason or not I really need help to know if there’re safe!
Because I think about a month ago I have been experienced itching skin especially on my face and arms and it looks like doesn’t go away any soon I also think that my skin looks like the people that have eczema dry itching skin kind of thing!
Please if anyone sees this post help and let me know what to do ASAP
Base on this info above I might be get them out for good “

October 19th, 2016 | 12:13 am

I am allergic to sulfer, about 2 months ago I put snake plants in my room to purifie the air as I heard some great reports,in the beginning I started to get the flew which doctors confirmed himophilia influencer, this was treated with several doses of different antibiotics. The himophilia influencer is gone but I’m progressively getting worse coughing up huge amounts of white flem, this keeps me awake and now I have chronic phatigu. All my testing has so far come up with unexplained reasons. Symptoms, slightly runny nose, repetitive conjunctivitis, non stop cough with very white flem and irritation of the palate. I have tried to research this but can’t get any answered, do you think it’s an allergy to snake plant? Please help
.

February 26th, 2017 | 5:37 pm
Sue:

Thought this was to discuss allergies. Only see 2 posts from people who think they are allergic to snake plant. I want to join their thought. I have a beautiful snake plant on my desk. I used to think I was allergic to my lap top but now maybe I am allergic to the plant. Anyone else have this problem?

August 11th, 2017 | 8:07 pm
Renée L.:

I just wanted to note that there is an exception to one of the “Low Allergy Plants” – Croton. I have one of these plants, but once in awhile, it gets a long stem with blooming, round little flowers on it. When this happens, my eyes gets watery, sting and swollen eyelids. I also get allergic rhinitis. This continues until it is done blooming and the flowers dry out. I have a lot of houseplants, so it took a couple times of this happening to figure out the culprit.

August 5th, 2018 | 9:27 am

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September 8th, 2018 | 7:02 pm
October 28th, 2018 | 2:26 pm
November 12th, 2018 | 12:21 am
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