Botanical Briefs: Australian Stinging Tree (Dendrocnide moroides)
Dendrocnide moroides (also known as gympie-gympie, mulberrylike stinging tree, or stinger) is arguably the most brutal of stinging plants, even leading to death in dogs, horses, and humans in rare cases. They can be recognized as shrubs with heart-shaped, serrated, dark green leaves that are covered in what appears to be soft downy fur with red to dark purple raspberries growing on long stems. After contact, there is immediate piloerection and local swelling, which may disappear after 1 hour or last as long as 24 hours, but the subjective pain, pruritus, and burning can persist for months. One can only treat conservatively with symptom management, and the most successful method of removing plant hair is hair removal wax strips, which are considered an essential component of a first aid kit where D moroides is found.
Practice Points
- Dendrocnide moroides is arguably the most brutal of stinging plants, even leading to death in dogs, horses, and humans in rare cases.
- Clinical observations after contact reveal immediate piloerection and local swelling, which may disappear after 1 hour or last as long as 24 hours, but subjective pain, pruritus, and burning can persist for months.
- The most successful method of removing plant hair is hair removal wax strips, which are considered an essential component of a first aid kit where D moroides is found.
Prevention and Treatment
Prevention—Dendrocnide moroides dermatitis is best prevented by avoiding contact with the plant and related species, as well as wearing upper body clothing with long sleeves, pants, and boots, though plant hairs can still penetrate garments and sting.2,3
Therapy—There is no reversal therapy of D moroides dermatitis but symptoms can be managed.4 For pain, analgesics, such as opioids, have been used; on occasion, however, pain is so intense that even morphine does not help.4,10
Systemic or topical corticosteroids are the main therapy for many forms of plant-induced dermatitis because they are able to decrease cytokine production and stop lymphocyte production. Adding an oral antihistamine can alleviate histamine-mediated pruritus but not pruritus that is mediated by other chemicals.11
Other methods of relieving symptoms of D moroides dermatitis have been proposed or reported anecdotally. Diluted hydrochloric acid can be applied to the skin to denature remaining toxin.4 The sap of Alocasia brisbanensis (the cunjevoi plant) can be rubbed on affected areas to provide a cooling effect, but do not allow A brisbanensis sap to enter the mouth, as it contains calcium oxalate, a toxic irritant found in dumb cane (Dieffenbachia species). The roots of the Australian stinging tree also can be ground and made into a paste, which is applied to the skin.3 However, given the stability of the toxin, we do not recommend these remedies.
Instead, heavy-duty masking tape or hot wax can be applied to remove plant hairs from the skin. The most successful method of removing plant hair is hair removal wax strips, which are considered an essential component of a first aid kit where D moroides is found.3
