FEATURE ARTICLE 2.0 Contact Hours Plant-Associated Dermatitis Karthik Iyer, Monica Rengifo-Pardo, Alison Ehrlich ABSTRACT: Poison ivy, poison oak, and poison sumac are history to identify patient use of plant-based products when well-known causes of plant-associated allergic contact evaluating dermatitis. dermatitis (ACD), but the spectrum of plant-associated ACD is an immune-mediated, Type IV hypersensitivity dermatoses covers these and much more. Plant-associated response to an allergen that contacts the skin. ACD is a dermatitis can be categorized into phytophotodermatitis, delayed hypersensitivity because it requires sensitization irritant contact dermatitis, contact urticaria, and ACD. The after primary exposure to the allergen; the cutaneous symp- focus of this article is ACD: the frequent causes, patch toms present after multiple exposures. Phytophotodermati- testing, association with cosmetic products, and patient tis is caused by plant photosensitizing agents, especially education. furocoumarins such as psoralen, and does not involve the Key words: Contact Dermatitis, Irritant Contact Dermatitis, immune system (McGovern & Barkley, 1998). ICD is the Phytophotodermatitis, Plant Dermatitis most common plant-associated dermatitis and is caused by a cutaneous irritant that triggers the skin’s innate im- ermatitisVa broad term describing inflam- mune system. Contact urticaria can be immunologic or mation of the skinVcan be subcategorized nonimmunologic. Immunologic contact urticaria (ICU) is into four types of cutaneous manifestations secondary to immunoglobulin E (IgE)-mediated mast cell on plant exposure: allergic contact derma- degranulation and is exacerbated by repeated exposure. titis (ACD), phytophotodermatitis, irritant Non-ICU is caused by plant toxins and is not triggered contact dermatitis (ICD), and contact urticarial (McGovern by the immune system (McGovern & Barkley, 1998). D& Barkley, 1998). Because of the ubiquitous nature of Patch testing is an important diagnostic tool that assists plants, education is necessary to prevent these cutaneous the physician in determining the cause of ACD. Multiple reactions from occurring, especially with the growing pop- allergens can be tested simultaneously to identify the trigger ularity of topical or ingestible products containing botan- of the dermatitis. Once the perpetrator is determined, the ical extracts (Morrow, Rapaport, & Strick, 1980). Patients next step is to educate the patient regarding avoidance to applying cosmetics and topical medicines containing bo- minimize further exposure. Prevention of recurrence is highly tanical extracts often forget to mention these products dependent on patient compliance because the best treatment when asked about nonprescription medications they are is avoidance of the allergen. using during the office visit. This may be because of the general population’s not being aware that natural and PHYTOPHOTODERMATITIS herbal products have the potential to cause cutaneous reac- Plant families with plants that are known to cause pho- tions (Kiken & Cohen, 2002). Therefore, it is the role of totoxicity include Rutaceae, Moraceae,andApiaceae (Lovell, the dermatology nurse or dermatologist to take a detailed 1997; Patel, Zahir, & Ehrlich, 2012). Examples of plants belonging to these families include carrots, parsnip, dill, celery, anise, hogweed, lime, and lemon. After a patient Karthik Iyer, MD, Department of Dermatology, George Washington comes in contact with a member of these plant families, University Medical Faculty Associates, Washington, DC. Monica Rengifo-Pardo, MD, Department of Dermatology, George photosensitizing agents are conferred to the patient’s skin. Washington University Medical Faculty Associates, Washington, DC. The photosensitizing agent in many of these mentioned Alison Ehrlich, MD, Department of Dermatology, George Washington plants is psoralen. Psoralen is a furocoumarin that is acti- University Medical Faculty Associates, Washington, DC. vated upon exposure to ultraviolet A radiation, resulting in Disclosure: Karthik Iyer, MD, received salary support in the form covalent DNA linkages that damage the epidermis and of a fellowship grant from Janssen Biotech, Inc. dermis. Cutaneous manifestations appear as painful, bullous, The authors declare no conflict of interest. and erythematous eruptions resulting commonly in chronic Correspondence concerning this article should be addressed to Alison Ehrlich, MD, Department of Dermatology, George Washington skin hyperpigmentation (Lovell, 1997; Patel et al., 2012). University Medical Faculty Associates, Washington, DC. Testing for this condition does not require the use of E-mail: [email protected] patch testing. Detailed history and physical examination DOI: 10.1097/JDN.0000000000000153 can identify this condition and its triggers. Treatment is 266 Journal of the Dermatology Nurses’ Association Copyright © 2015 Dermatology Nurses' Association. Unauthorized reproduction of this article is prohibited. symptomatic, and patient education regarding avoidance this is called the sensitization phase. Upon reexposure, IgE of triggers is the best method of prevention. antibodies attached to mast cells and basophils cross- link via binding to the allergen causing degranulation and IRRITANT CONTACT DERMATITIS release of vasoactive substances. Because of this mechanism of ICU, patients with atopy have a higher likelihood of Mechanical ICD developing ICU (McFadden, 2014). This is the result of physical injury to the skin caused by a Interestingly, fruits and vegetables are a common trig- plant’s trichomes, spines, glochids, or thorns. Trichomes ger of ICU. Fruits were found to have cross-reactivity with (hairs) of plants can breach the epidermis and trigger a plant pollens mediating the ICU in plant-pollen-allergic papular eruption (Modi, Doherty, Katta, & Orengo, 2009; patients. For example, patients with ragweed allergy (see Patel et al., 2012). The most well-known plant containing Figure 1) may have a cross-reaction after eating or touching V spines is the cactus. Cacti also have glochids small, barbed melons, resulting in contact urticarial (Konstantinou & V hairs that may trigger a more significant cutaneous erup- Grattan, 2008). Plants are an important trigger of ICU tion than the larger spines. Spine, glochid, and thorn ICD among gardeners and greenhouse workers with the most presents as erythematous papules and nodules and may common culprits being Christmas cactus, Barberton daisy, have a central black dot with erythema where the mechan- and Madagascar jasmine (Paulsen, Skov, & Andersen, ical irritant entered (Modi et al., 2009; Patel et al., 2012). 1998). The allergen commonly involved in the mediation With physical trauma, secondary infection is a common of ICU is suspected to be profilin, an IgE-binding protein complication (Modi et al., 2009). (Amaro & Goossens, 2008). Diagnosis of ICU is performed via the open test (rubbing suspected causative agent on skin Chemical ICD for 5Y10 seconds and observing for 160 minutes), skin This kind of ICD involves deposition of plant chemicals prick testing with commercial reagents, or allergen-specific onto the epidermis after physical contact and subsequent IgE titers. Reactions usually appear within 10Y20 minutes, inflammation. An important cause of chemical ICD is calcium oxalate, which is a common salt found in plant cells as raphidesVneedlelike crystals. After exposure, the plant cell releases the raphides onto the skin or mucosal surface. These raphides cause physical trauma and irrita- tion but are more important in mediating the penetration of other plant chemicals (Modi et al., 2009). Dieffenbachia is a commonly found household ornamental plant, and contact results in a raphide-mediated vesicular and bullous eruption associated with pruritus and erythema (Patel et al., 2012). Daffodils are another cause of chemical ICD. ‘‘Daffodil itch’’ is commonly found in florists and presents as dry skin, scaling, and erythema of the fingertips and hands because of contact with calcium oxalate raphides found in mucus from the stems and the sap from the bulbs of daffodils (Bruynzeel, 1997). Capsaicin is a commonly used spice today and is found in chili peppers (Capsicum species). Capsaicin activates sensory neurons, resulting in activation and dose-dependent cutaneous burning and erythema as well as glandular secretion and vasodilation (McGovern & Barkley, 1998; Williams, Clark, & Dunford, 1995). Similar to that of phytophotodermatitis, diagnosis of ICD relies mainly on detailed history regarding plant contact/ exposure and physical examination findings. Patch testing does not play an important role in ICD, except to rule out the presence of ACD (Rietschel, 1977). CONTACT URTICARIA This condition can be divided into two categories: immu- nologic and nonimmunologic. ICU is a Type I hypersen- sitivity reaction facilitated by IgE. Allergen-specific IgE is produced in the body after first exposure to an allergen; FIGURE 1. Ragweed, a member of the Compositae family. VOLUME 7 | NUMBER 5 | SEPTEMBER/OCTOBER 2015 267 Copyright © 2015 Dermatology Nurses' Association. Unauthorized reproduction of this article is prohibited. and the treatment is symptomatic management as the con- Urushiol is found not only in the leaves but also in the stems, dition tends to resolve spontaneously with minimization of roots, and fruit of Toxicodendron plants. For urushiol to allergen exposure (Maibach, 1976). Patch testing is not be released onto human skin, plant