Plants and their products cause a variety of adverse cutaneous reactions, including the vast majority of cases of allergic contact dermatitis. This chapter describes the small minority of plants that cause such problems. (Reactions to members of the kingdoms Fungi and Protista are less common and will not be discussed here.) Plant dermatoses will be presented based on both their clinical features and the plant families that cause them. The major plants that cause allergic contact dermatitis (poison ivy, chrysanthemums, and their relatives) are reviewed.

Plant reactions can be classified into urticaria (immunologic and toxin-mediated; see  Chs 17 &  19), irritant dermatitis (mechanical and chemical), phototoxic dermatitis (phytophotodermatitis) and allergic contact dermatitis. Table 18.1 lists the most common plant reactions.