Plant exposures are some of the most frequent poisonings reported to poison control centers. Exposures to plants containing oxalate crystals, such as Philodendron and Dieffenbachia, are among the most common toxic plant exposures reported in the United States.
For the past 200 years, the irritant properties of the Dieffenbachia plant have had various uses, including punishing slaves and treating gout, impotence, and frigidity. Today, plants containing oxalate are admired for their ornamental beauty and found in public places and homes.
The following plants contain oxalates:
Anthurium (Anthurium species)[1]
Arum, Araceae (Arisaema species)
Caladium (Caladium bicolor)
Calla lily (Zantedeschia species)
Chinese evergreen (Aglaonema species)
Dieffenbachia (Dieffenbachia species) (see the image below)[2]
Jack-in-the pulpit (Arisaema triphyllum) (see the image below)
Monstera, Ceriman (Monstera deliciosa)
Nephthytis (Syngonium podophyllum)
Philodendron (Philodendron species)
Pothos or Hunter's robe (Epipremnum aureum)
Skunk cabbage (Symplocarpus foetidus) (see the images below)
Nonsoluble calcium oxalate crystals are found in plant stems, roots, and leaves. The stalk of the Dieffenbachia plant produces the most severe reactions. These needlelike crystals produce pain and edema when they contact lips, tongue, oral mucosa, conjunctiva, or skin.[3] Edema primarily is due to direct trauma from the needlelike crystals and, to a lesser extent, by other plant toxins (eg, bradykinins, enzymes).[4, 5]
Philodendron and Dieffenbachia exposures are among the most common plant exposures reported to poison control centers. According to the 2017 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS), 4844 single exposures were documented for oxalate plant poisonings.[6]
The majority of oxalate plant exposures occur in children younger than 5 years while sampling houseplants in the home. The 2017 Annual Report of the American Association of Poison Control Centers' NPDS reported 3557 oxalate plant exposures in those younger than 6 years, 709 exposures in those aged 6-19 years, and 467 exposures in those older than 19 years.[6]
Most patients who have been exposed to plants containing oxalates completely recover. In most cases, nonsoluble oxalate plants produce self-limited symptoms and clinical manifestations. Significant morbidity or mortality is extremely rare. However, there are case reports of severe oropharyngeal inflammation and edema, with impending obstruction of the upper airways.[7]
The 2017 Annual Report of the American Association of Poison Control Centers' NPDS reported 960 minor outcomes, 46 moderate outcomes, no major outcomes, and no deaths from oxalate plant exposures.[6]
Decontaminate mouth, eye, and skin by physically removing all plant material. Treat eye and skin exposure with copious water irrigation. Rescuers should protect themselves from contact with plant materials.
Most exposures are self-limited and only require analgesics for patient comfort.
For oral exposures, physically remove any plant material in the oral cavity. Assess for any airway compromise. Individuals without airway compromise can drink cold liquids and eat crushed ice, ice cream, or frozen ice pops or desserts for relief.[7] Oral swishing with diphenhydramine elixir provides local anesthetic and antihistaminic effects. Individuals with laryngeal edema may be treated with antihistamines and observed and/or admitted until edema improves. No clinical data support use of steroids in laryngeal edema induced by oxalate-containing plants.
Treat eye exposures with copious water irrigation. Employ slit lamp examination and fluorescein staining to rule out corneal involvement.
Skin exposures require irrigation with fluid and local wound care. Some individuals may develop a contact dermatitis.
Most oxalate exposures do not require any follow-up.
Nearly all cases of houseplant exposures involving oxalate-containing plant species are managed at home in consultation with a regional poison control center. Poison control centers may be helpful with plant identification, particularly if a fax copy or digital picture of the plant can be transmitted. Patients with eye involvement should follow up with an ophthalmologist.
Clinical Context:
DOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, with upper GI disease, or who are taking oral anticoagulants.
Pain control is essential to quality patient care. Analgesics ensure patient comfort, which is beneficial for patients who have sustained trauma or sustained injuries.
Jason F Kearney, MD, MBA, Facility Medical Director, Emergency Department, TeamHealth Providence Centralia
Disclosure: Nothing to disclose.
Coauthor(s)
William K Chiang, MD, Associate Professor, Department of Emergency Medicine, New York University School of Medicine; Chief of Service, Department of Emergency Medicine, Bellevue Hospital Center
Disclosure: Nothing to disclose.
Specialty Editors
John T VanDeVoort, PharmD, Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals
Disclosure: Nothing to disclose.
Chief Editor
Sage W Wiener, MD, Assistant Professor, Department of Emergency Medicine, State University of New York Downstate Medical Center; Director of Medical Toxicology, Department of Emergency Medicine, Kings County Hospital Center
Disclosure: Nothing to disclose.
Additional Contributors
Miguel C Fernandez, MD, FAAEM, FACEP, FACMT, FACCT, Associate Clinical Professor, Department of Surgery/Emergency Medicine and Toxicology, University of Texas School of Medicine at San Antonio; Medical and Managing Director, South Texas Poison Center
Disclosure: Nothing to disclose.
Acknowledgements
Michael Hodgman, MD Assistant Clinical Professor of Medicine, Department of Emergency Medicine, Bassett Healthcare
Michael Hodgman, MD is a member of the following medical societies: American College of Medical Toxicology, American College of Physicians, Medical Society of the State of New York, and Wilderness Medical Society
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