Dermatitis-producing Anacardiaceae of the Caribbean area

Abstract

Although the Caribbean Islands and Central America form a transitional geographic bridge between North and South America, the distribution of members of the Anacardiaceae (poison ivy family) between these two continents is abrupt. Florida and the extreme northwestern Bahamas mark the southernmost limit of the subspecies of poison ivy that extends along the whole of the eastern seaboard to Nova Scotia. Two of the three subspecies of poison ivy of Mexico have their northern limit in the Mexican border counties of Texas and Arizona, the third is entirely selfcontained. Western poison oak of the Pacific seaboard of the United States northward into British Columbia has, as its southernmost limit, north Baja California, where it is sparse.Of three other genera of dermatitis-producing Anacardiaceae in the Caribbean and Central America, one, Metopium, is represented by a single species in south Florida. The other two, Comocladia and Pseudosmodingium, do not extend into either North or South America. From the genera of South American dermatitis-producing Anacardiaceae, only two species are indigenous to the southern portion of Central America: the small trees, Toxicodendron striatum and a species of Mauria. The remainder of this latter genus is restricted to the Andes. Both will be discussed in greater detail in chapter 21.Three species of Anacardiaceae associated with dermatitis have been introduced and, in some areas, are escaped from cultivation and established into the regional flora. From South America, Schinus terebinthifolius was introduced as an ornamental and the cashew, Anacardium occidentale, for its edible nut. The mango, Mangifera indica, from Indo-Asia, is grown in tropical areas world-wide for its edible fruit. Both the mango and the cashew belong to the botanic tribe Mangifereae and exhibit some important distinctions from the tribe Rhoideae, to which all the other genera of Anacardiaceae in this chapter are assigned.1 Other than the synopsis given by Mitchell and Rook,2 there have been no comprehensive reviews of the dermatologic aspects of the Anacardiaceae for this geographic area. Since floristic accounts are scattered through a number of publications, an unusual amount of space in this review will be devoted to referenced descriptions of growing areas and local terminology. Nicaragua, El Salvador, and Honduras have not been the subjects of recent floras. Hispaniola, Puerto Rico, and the Lesser Antilles currently are undergoing revision of their floras, but this task is only partially completed. The listing of dermatitis-producing Anacardiaceae from these areas should be considered incomplete. In some of the islands of the Lesser Antilles, expected plants are missing as the result of past agricultural practice. This is particularly notable for the island of Dominica.There are few medical reports of plant dermatitis from Central America and the Caribbean. Except for the introduced species, we must depend mostly upon comments by botanists in annotations on herbarium specimens or in floras. Chemical studies on sensitizers, except for economically important species, are nonexistent. Even simple tests to determine cross-sensitization to other members of the Anacardiaceae seem not to have been conducted. All of the species in the following discussion are assumed to produce delayed contact sensitivity analaogous to poison ivy and poison oak.