close encounters with the environment

Botanical Briefs: Dumb-cane—Dieffenbachia picta (Lodd.) Schott Thomas W. McGovern, MD

Cutaneous Manifestations with the bruised or broken mate- Dieffenbachia picta received the epithet rial may cause severe blistering and in- “Dumb-cane” because chewing the flammation. Chewing the stem has leaves can lead to salivation, burning, rarely led to death in children and pets.1 mucosal edema, perioral edema, and blisters causing hoarseness or aphonia. Family The juice of D picta leaves may cause The family, which also en- intense pruritus and irritation. Contact compasses the Arum, is large and diverse and includes a number of eco- nomically important and decorative Dr. McGovern is in private practice in Fort , including other common office Wayne, Indiana. or lobby plants, such as the philoden- REPRINT REQUESTS to Fort Wayne Dermatology, PC, 5750 Falls Drive, Fort Wayne, dron (Philodendron scandens) and the IN 46804. peace lily (Spathiphyllum walisii).

FIGURE 1. Dieffenbachia picta (Lodd.) Schott demonstrating pointed, ovate leaves with central, blotchy yellow-white and peripheral green variega- tion (Author’s desk at home, February 1998). It is an easy plant to grow and is difficult to kill.

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Distribution of Plant crystals) and druses (spherical aggre- The genus Dieffenbachia includes about gates of crystals), but their irritant ef- 30 native to tropical America fect on skin and mucous membranes and the West Indies. Certain species are believed to be increased by the pres- are widely cultivated for their decora- ence of other proteins. Calcium oxalate tive foliage and are commonly seen in is a water insoluble salt that is ejected homes, hotel and bank lobbies, waiting from the plant when exposed to water, rooms, and restaurants.2 as in the skin or mucosa.3,4 Tests on rabbit eyes have shown se- Dermatitis-Inducing Plant Parts vere irritation with the juice of D picta, The leaves, stem, and fruit are notori- the toxicity being associated with a la- ous causes of hoarseness and aphonia; bile proteinase present in the sap. This however, the entire plant contains cal- proteinase, named dumbcain, has been cium oxalate raphides. isolated from both D picta and D sequine, and it may be injected intra- Nomenclature dermally with the aid of calcium ox- D picta is also known as Dumb-cane, alate raphides. D picta leaves contain Dumb Plant, Tuft Root, Mother-in- large (130–150 µm by 3 µm) and small Law’s Tongue Plant, Otó de Lagarto, (10–20 µm by 1 µm) calcium oxalate Rábano, and Cimarrón. Dieffenbachia is raphides that are sharply pointed at named after J.F. Dieffenbach, while both ends, and they are contained in picta is from the Latin pictus meaning unusual, randomly scattered capsular painted or colored and denotes the var- cells from which they may be expelled iegated leaves. through the ends.2 Antihistamines af- ford some protection against the effects Identifying Features/Plant Facts of the juice on the oral cavity, but treat- Members of the family Araceae share a ment with cortisone merely delays the common floral structure. The small reaction.3 male and female flowers are borne on a club-like stem (spadix) surrounded by REFERENCES a modified leaf (spathe). The peace lily, 1. Mabberley DJ. The Plant-Book. Cambridge, with its large white spathe enveloping Mass: Cambridge University Press; 1997: the long spadix is a good example. 228. Dieffenbachias are stout herbs with 2. Schmidt RJ. Botanical dermatology data- leaves that typically have large, cen- base. Available at: http://bodd.cf.ac.uk. trally splotchy-white or yellow areas Accessed February 18, 2000. (Figure 1). In centuries past, D picta 3. Lovell CR. Plants and the Skin. Oxford, Eng- leaves were used to torture slaves.1 land: Blackwell Scientific Publications; 1993:54. Irritants 4. Stoner JG. Miscellaneous dermatitis- All Dieffenbachia species contain cal- inducing plants. Clin Dermatol. 1986;4:94- cium oxalate raphides (needle-like 101.

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