Plant Dermatitis: More Than Just Poison Ivy

This is the authors' abstract. We don't add key points for this paper.

Plants can cause allergic contact dermatitis (ACD), mechanical irritant contact dermatitis, chemical irritant contact dermatitis, light-mediated dermatitis, and pseudophytodermatitis.Allergic contact dermatitis to chemicals in the Toxicodendron genus, which includes poison ivy, poison oak, and poison sumac, is the most common cause of plant ACD; however, many other plants, such as Compositae, Alstroemeriaceae, and Rutaceae plants also are important causes of dermatitis.In individuals with recurrent ACD from plants other than Toxicodendron, patch testing can be used to identify the source of allergic reactions to plant species.This article provides an overview of the various plant dermatoses, common culprits of plant dermatitis, and diagnostic and therapeutic options for plant dermatoses.Cutis.2021;108:124-127. Plants can contribute to a variety of dermatoses.The Toxicodendron genus, which includes poison ivy, poison oak, and poison sumac, is a well-known and common cause of allergic contact dermatitis (ACD), but many other plants can cause direct or airborne contact dermatitis, especially in gardeners, florists, and farmers.This article provides an overview of different plant-related dermatoses and culprit plants as well as how these dermatoses should be diagnosed and treated. EpidemiologyPlant dermatoses affect more than 50 million individuals each year.1,2 In the United States, the Toxicodendron genus causes ACD in more than 70% of exposed individuals, leading to medical visits.3 An urgent care visit for a plantrelated dermatitis is estimated to cost $168, while an emergency department visit can cost 3 times as much.4 Although less common, Compositae plants are another important culprit of plant dermatitis, particularly in gardeners, florists, and farmers.Data from the 2017-2018 North American Contact Dermatitis Group screening series (N=4947) showed sesquiterpene lactones and Compositae to be positive in 0.5% of patch-tested patients.5 Plant Dermatitis ClassificationsPlant dermatitis can be classified into 5 main categories: ACD, mechanical irritant contact dermatitis, chemical irritant contact dermatitis, light-mediated dermatitis, and pseudophytodermatitis.6 Allergic contact dermatitis is an immune-mediated type IV delayed hypersensitivity reaction.The common molecular allergens in plants include phenols, α-methylene-γ-butyrolactones, quinones, terpenes, disulfides, isothiocyanates, and polyacetylenic derivatives.6 Plant contact dermatitis due to mechanical and chemical irritants is precipitated by multiple mechanisms, including disruption of the epidermal barrier and subsequent cytokine release from keratinocytes.7 Nonimmunologic contact urticaria from plants is thought to be a type of irritant reaction precipitated by mechanical or chemical trauma.