Irritant Contact Dermatitis from Plants

Gunjan M. Modi; Christy B. Doherty; Rajani Katta; Ida F. Orengo

Disclosures

Dermatitis. 2009;20(2):63-78. 

In This Article

Abstract and Introduction

Abstract

Irritant contact dermatitis (ICD) from plants is a very common phenomenon as potentially irritant plants and plant products are commonly found in the everyday environment, including the home, garden, workplace, and recreational setting. It is therefore essential to have a basic understanding of the various plant-derived physical and chemical irritants. ICD from plants is commonly divided into mechanical irritant contact dermatitis (MICD) and chemical irritant contact dermatitis (CICD). The common mechanical plant irritants include thorns, spines, glochids, trichomes, and sharp-edged leaves. Many chemical irritants have yet to be elucidated, but known culprits include calcium oxalate, protoanemonin, isothiocyanates, bromelain, diterpene esters, alkaloids, and other chemical irritants such as naphthoquinone and acids. This review details the major plant contributors to MICD and CICD, along with their respective irritants. The clinical presentations seen in ICD (versus other plant dermatoses) will also be described, along with diagnostic considerations and exposure data. We also review mechanisms for the development of ICD and current treatments for ICD from plants.

Introduction

Skin reactions due to plants are common, as plants are ubiquitous and exhibit a number of physical and chemical properties that may result in harm. Four major types of cutaneous reactions following exposure to plant or plant-derived products have been described: irritant contact dermatitis, contact urticaria, allergic contact dermatitis, and phytophotodermatitis ( Table 1 ). The term "irritant contact dermatitis" (ICD) is used to describe a cutaneous inflammatory response to physical or chemical injury. Although inflammatory and immunologic mediators may be activated, generally only innate immune response mechanisms are involved, along with an absence of memory T-cell function or antigen-specific immunoglobulins.[1,2]

ICD is very common, accounting for approximately 80% of all contact dermatitis reactions and the majority of occupational and plant dermatoses.[3,4] Plant-related ICD, as with ICD in general, has many diverse presentations. Irritant reactions to plants may produce a wide range of clinical findings. Mild chronic eczematous dermatitis may occur owing to irritant hairs on some plants. Severe acute toxic reactions with necrosis may be seen following exposure to potent alkaloids from plant sap.

Unlike in the case of allergic contact dermatitis, anyone exposed to a cutaneous irritant can potentially be affected. Irritation and its severity depends on the barrier function integrity of the individual's skin, the potency and amount of irritant to which one is exposed, and the duration of irritant exposure.

ICD can be subcategorized based on the nature of the irritant. Chemical irritants are responsible for chemical ICD (CICD), and physical irritants result in mechanical ICD (MICD) via mechanical trauma or microtrauma.[5] There is, however, frequent overlap, and a presentation of plant-induced ICD may be secondary to more than one factor. An example is reactions to Narcissus bulbs: physical microtrauma from handling Narcissus bulbs may enhance the cutaneous penetration and effects of chemical irritant calcium oxalate crystals.[6]

The potential of various features of a single plant to contribute to a case of ICD makes the study of ICD from plants especially challenging. Further complicating the clinical picture are the facts that irritant skin damage by plants can render individuals more susceptible to allergic sensitization, and that many allergenic chemicals are also irritants by nature.[7]

Because of these features, the study of ICD from plants is challenging. We review the major plant contributors to MICD and CICD, along with their respective irritants. The clinical presentations seen in ICD (vs other plant dermatoses) will also be described, along with diagnostic considerations and exposure data. We also review mechanisms for the development of ICD and current treatments of ICD from plants.

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