FS11.5Toxicodendron dermatitis in the United Kingdom

We describe two cases of Toxicodendron dermatitis, one acquired in the United States but presenting in the United Kingdom, the other a recurrent dermatitis following importation to the UK. Poison ivy, poison oak and poison sumac are native to North America and belong to the genus Toxicodendron. This group of plants is of interest to the dermatologist because they contain a mixture of potent sensitisers which cause a severe allergic contact dermatitis. The dermatitis can present to the dermatologist in Europe after an individual has been in contact with the plant whilst visiting an endemic area. The plants have the potential to grow in the UK and it is therefore possible for an individual to be sensitised and subsequently to develop the rash without leaving the UK. A 35‐year‐old American man who lived in the UK visited his family in Marietta, Georgia USA. Shortly before his return to the UK he cut some plants back in his mother’s garden. Two days following his arrival back in the UK he developed a widespread pruritic and painful vesicobullous eruption. He required admission for intensive potent topical corticosteroid therapy and the eruption settled over the next two weeks. The plant he had been pruning was subsequently identified as poison sumac (Toxicodendron vernix). A 54‐year‐old woman living in Wales was referred to the Contact Dermatitis Investigation Unit because during the summer months for the previous four years she had experienced an intermittent, intensely pruritic, vesicular and in parts linear eruption affecting her face, arms and legs. This responded slowly to potent topical corticosteroids. She is a keen gardener and suspected that it was related to a plant in her garden. She was patch tested to our Standard Series, Plant Series and all the plants in her garden. She showed ++ allergic reactions to sodium metabisulphite, propolis and a strong vesicular reaction to the leaf of one of the plants from her garden Inspection of the plant revealed that it had three leaflets per stem. She had taken a cutting whilst visiting friends in Pennsylvania in 1996 and on returning to the UK had planted it in her garden. It grew but had never flowered or produced seeds. Once the cause of her dermatitis had been confirmed our patient took the necessary protective measures and removed the plant including its roots from her garden. She has not experienced any further problems with her skin. She contacted her friends in the USA who knew precisely where she had picked the plant. A further specimen was taken to the local Conservation Office where it was confirmed to be poisonivy. Poison ivy and poison sumac belong to the genus Toxicodendron which is native to North America and Mexico. They cause an allergic contact dermatitis when there is exposure to a bruised portion of the plant. This leads to the oleoresin, urushiol coming into contact with the skin. 25–60% of North Americans are reported be allergic to poison ivy and its relatives. The importation of plants into the UK is restricted by law. It is clear that this plant grew in its new habitat but did not extend beyond the confines of the garden. With frequent and more extensive air travel it seems reasonable to speculate that similar occurrences have taken place and that plants not endemic to Europe should be considered in those with suspected plant dermatitis.     

Black-spot poison ivy dermatitis. An acute irritant contact dermatitis superimposed upon an allergic contact dermatitis

A black spot in the epidermis over a blister of poison ivy dermatitis is an uncommon finding. Four patients with the phenomenon are described. Histologic and histochemical studies were made on biopsy material and the blackish deposit on the skin surface was compared with black deposits in and on leaves of the species of poison ivy. This examination revealed a yellow, amorphous substance on the stratum corneum of the lesions and a similar substance in and on leaves of the poison ivy plant, Toxicodendron radicans ssp. negundo. Associated with the pigmentary deposits there were distinct changes of acute irritant contact dermatitis superimposed upon allergic contact dermatitis. Our findings support the view that the black material is the oleoresin of the plant, and that this substance behaves both as an irritant and an allergen.     

Treatment of toxicodendron dermatitis (poison ivy and poison oak)

Toxicodendron dermatitis results from a reaction to an oil soluble oleoresin that is present in many parts of the poison ivy and poison oak plants. Prophylactic measures include avoidance, protective clothing, barrier creams and hyposensitization. Treatments include washing the area immediately with a solvent suitable for lipids and the use of anti-inflammatory agents, especially corticosteroids.     

Black spot poison ivy: A report of 5 cases and a review of the literature.

Black-spot poison ivy dermatitis is a rare manifestation of a common condition. It occurs on exposure to the resins of the plants of the Rhus family also known as Toxicodendron. We describe 5 patients with black deposits on their skin and clothing after contact with poison ivy and review the literature reflecting different aspects of this phenomenon including clinical presentation, histologic findings, and historical background.     

Recognizing the Toxicodendrons (poison ivy, poison oak, and poison sumac)

Poison ivy, poison oak, and poison sumac are now classified in the genus Toxicodendron which is readily distinguished from Rhus. In the United States, there are two species of poison oak, Toxicodendron diversilobum (western poison oak) and Toxicodendron toxicarium (eastern poison oak). There are also two species of poison ivy, Toxicodendron rydbergii, a nonclimbing subshrub, and Toxicodendron radicans, which may be either a shrub or a climbing vine. There are nine subspecies of T. radicans, six of which are found in the United States. One species of poison sumac, Toxicodendron vernix, occurs in the United States. Distinguishing features of these plants and characteristics that separate Toxicodendron from Rhus are outlined in the text and illustrated in color plates.     

Phytodermatitis.

BACKGROUND: Most dermatologists can recognize the classic patterns of presentation of plant contact dermatitis; however, few can recognize the offending plants or know the name and chemical structure of the allergens or irritants that they contain. OBJECTIVE: Five basic clinical patterns of phytodermatitis are reviewed: 1) allergic phytodermatitis, 2) photophytodermatitis, 3) irritant contact dermatitis, 4) pharmacologic injury, and 5) mechanical injury. The plants responsible for each pattern are presented by families, according to current scientific taxonomy. The chemical structure of the offending substances is described, and principles of investigation, prevention, and treatment are outlined. CONCLUSIONS: Plant contact dermatitis remains an extremely vast and complex topic. Exotic plants and woods are now present in our gardens and homes. The newfound interest in aromatherapy, phytotherapy, and so-called "natural" therapies is the cause of a tremendous increase in exposure to plant products and extracts. This is responsible for the appearance of atypical patterns of plant contact dermatitis with which the practising dermatologist must become familiar.     

Is it,or isn't it? Poison ivy look-a-likes

Poison ivy causes more allergic contact dermatitis (ACD) than any other cause. Although physicians rightfully focus on the treatment of the dermatitis, prevention will be aided by recognition of the foreboding plant. Likewise, many other plants can masquerade as poison ivy and cause one to needlessly curtail his or her activities because of fear of a bad reaction. The most common poison ivy pretenders in the United States are discussed, and distinguishing plant characteristics are highlighted.     

Toxicodendron radicans dermatitis with black lacquer deposit on the skin

Four patients with clinical Toxicodendron dermatitis (poison ivy) presented with dramatic black lacquer-like deposits on several lesions. This black deposit was also observed at sites of injury on poison ivy plants and was reproduced on volunteers by the application of plant sap on the skin. Histologically, the observed material was identified in the stratum corneum. This little-recognized phenomenon has been mentioned in past dermatologic literature.     

Smodingium allergenic Anacardiaceae in South Africa

The first case reports of genuine poison ivy dermatitis in South Africa appeared in 1959.¹ Eight patients were seen who had developed the rash following contact with a creeper in a hedge in Olifantsfontein near Pretoria. The creeper was identified as Toxicodendron radicans and had presumably been imported from North America, since it is not indigenous to South Africa. Similar cases have been seen since then in Johannesburg.²In 1963, seven patients from Pretoria and Johannesburg with a unique dermatitis of “poison-ivy type” were reported.³ These patients had not been exposed to imported American poison ivy but had reacted to an indigenous plant identified as Smodingium argutum, known by various common names, including tovana and rainbow leaf. It transpired that Smodingium dermatitis had been recognized by tribal blacks, foresters, botanists, horticulturists, and amateur gardeners for many years before the medical profession became aware of it. In subsequent years, this type of dermatitis became widely recognized and many more cases were seen, leading to further case studies² and investigations.^4,5In 1971. four South African patients were reported with a similar type of “poison ivy” dermatitis who had been exposed to the wax tree, Toxicodendron succedanea, an oriental sumac.² It became clear from cross-sensitivity reactions in certain patients that there were antigenic similarities between the oleoresins from S. argutum, T. radicans and T. succedanea, all members of the family Anacardiaceae.² An identical dermatitis is produced by all three plants.     

Kontaktallergie auf Poison ivy (Toxicodendron spp.)

Within 3 days two female patients presented with an eruption featuring erythema, edema, vesicles and bullae. We suspected poison ivy allergy which was subsequently proven by history and positive patch tests. In Germany the risk of specific hypersensitivity to Toxicodendron species is low, since the distribution of such plants is confined to botanical gardens. Other species belonging to the family of Anacardiaceae contain urushiols as well (e.g., mango, cashew) and may cause allergic contact dermatitis.     

Contact dermatitis from Grevillea''Robyn Gordon''

Grevillea‘Robyn Gordon’is an Australian hybrid plant which may cause allergic contact dermatitis. Over the past 8 years, in bag been planted extensively in Australia and is now being exported to the United Slates mid other Western countries. Recently, fin explosion in incidence of contact dermatitis due to this plant has been seen. 24 patients who were suspected of being sensitive to it were patch tested to fresh plant and extracts with confirmation of sensitivity. A cross sensitivity to Toxicodendron was demonstrated clinically and on patch testing. The allergen in Toxicodendron, 3 pentadecylcatechol, is closely linked in chemical structure to 5-penladecylresorcinol. present in Grevillea banksii and tridecylresorcinol in Grevillea robusta. Patch letting in patients sensitive to Grevillea‘Robyn Gordon’with tridecylresorcinol produced positive reactions, thus implicating the sensitizing role of long chain alkyl resorcinols in Grevillea‘Robyn Gordon’allergy. There is a likelihood that (his sensitizing potential extends to other plants of the Grevillea genus, e.g. Grevillea robusta. With the spread of Grevillea‘Robyn Gordon’to other markets, this problem will become increasingly common.     

Exploring the mango-poison ivy connection: the riddle of discriminative plant dermatitis

A relationship between sensitivity to poison oak or poison ivy and mango dermatitis has been suggested by previous publications. The observation that acute allergic contact dermatitis can arise on first exposure to mango in patients who have been sensitized beforehand by contact with other urushiol-containing plants has been documented previously. We report 17 American patients employed in mango picking at a summer camp in Israel, who developed a rash of varying severity. All patients were either in contact with poison ivy/oak in the past or lived in areas where these plants are endemic. None recalled previous contact with mango. In contrast, none of their Israeli companions who had never been exposed to poison ivy/oak developed mango dermatitis. These observations suggest that individuals with known history of poison ivy/oak allergy, or those residing in area where these plants are common, may develop allergic contact dermatitis from mango on first exposure. We hypothesize that previous oral exposure to urushiol in the local Israeli population might establish immune tolerance to these plants.     

Three cases of severe Rhus dermatitis in an English primary school

We report three paediatric cases of severe allergic contact dermatitis caused by a Japanese lacquer tree (Rhus verniciflua), which is a rare specimen plant in the UK. The diagnosis of allergic contact dermatitis produced by plants that are not indigenous to a particular country is more likely to be delayed, as well as mistaken for cellulitis.     

Occupational contact dermatitis

The dermatologist should be aware of the many facets of occupational skin diseases, which can be caused by physical, chemical, and biological insults. The most common manifestation of occupational skin diseases is contact dermatitis (both irritant and allergic). Three factors point out the importance of occupational skin diseases as diseases that have a public health impact: 1) occupational skin diseases are common; 2) they often have a poor prognosis; and 3) they result in a noteworthy economic impact for society and for an individual. They are also diseases amenable to public health interventions. Specific industries and exposures may put a worker at risk of occupational contact dermatitis. The accuracy of the diagnosis of occupational contact dermatitis is related to the skill level, experience, and knowledge of the medical professional who makes the diagnosis and confirms the relationship with a workplace exposure. Prevention of occupational contact dermatitis is important, and a variety of prevention strategies are available.     

Tomato contact dermatitis

The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate‐type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts. This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat‐stable and heat‐labile constituents seem to be involved. The fruit contains fragrance compounds that are also present in Myroxylon pereirae (balsam of Peru), possibly accounting for cross‐reactivity. The proteins in pulp and peel may contribute to protein contact dermatitis. Until more is known about the allergens, the diagnosis of contact dermatitis caused by tomato plants and fruit may be established with the use of ether extracts and fresh fruits, respectively.     

A study of cross-reactions between mango contact allergens and urushiol

The allergens causing mango dermatitis have long been suspected to be alk(en)yl catechols and/or alk(en)yl resorcinols on the basis of observed cross-sensitivity reactions to mango in patients known to be sensitive to poison ivy and oak (Toxicodendron spp.). Earlier, we reported the 3 resorcinol derivatives: heptadecadienylresorcinol (I), heptadecenylresorcinol (II) and pentadecylresorcinol (III); collectively named 'mangol', as mango allergens. In this study, we extracted the 1st 2 components (I and II) from the Philippine mango, adjusted them to 0.05% concentration in petrolatum and patch tested the components on 2 subjects with mango dermatitis. Both subjects reacted to I. 1 subject also elicited a weaker positive reaction to II. To investigate the cross-reaction between mangol and urushiol, we also patch tested the same subjects with urushiol. The subject sensitive to II reacted to urushiol. 6 subjects with a history of lacquer contact dermatitis and positive reactions to urushiol were similarly patch tested. 5 persons reacted to I. 2 subjects also exhibited a slower but positive reaction to II. This is the 1st report in which heptadec(adi)enyl resorcinols known to be present in mango have been shown to elicit positive patch test reactions in mango-sensitive patients.     

Quantitation and cloning of human urushiol specific peripheral blood T-cells: isolation of urushiol triggered suppressor T-cells

A limiting dilution assay was developed to quantitate urushiol (the antigen of poison ivy; Toxicodendron radicans) specific T cells from peripheral blood of a patient with a history of rhus (poison ivy) dermatitis. It was found that maximal sensitivity with minimal nonspecific proliferation could be produced with the use of 5 U/ml of recombinant IL2 added to the assay on day 6. This donor was found to have a frequency of urushiol specific peripheral blood T cells of (1/2935). Five interleukin 2 (IL2) dependent urushiol specific T-cell clones were generated from the peripheral blood of this patient. These T-cell clones had a CD8+ (T8+) phenotype and proliferated specifically to both extracts of Toxicodendron radicans (poison ivy) leaves and pure urushiol. Pentadecylcatechol was an inferior antigen, only stimulating proliferation of one clone. The ability of all clones to proliferate to pure urushiol, despite their having been induced with leaf extract, suggests that urushiol, or closely related catechols, represent the only allergenic constituents of Toxicodendron radicans. Lymphokine production in response to antigen varied between (0.6-5.0) units/ml of interleukin 2 (IL2) and (1.0-120) units/ml of gamma interferon. Although none of the clones showed significant cytotoxicity against NK targets, three of five lines showed considerable cytotoxicity against concanavalin A treated (lectin approximated) targets. However, cytotoxicity for rhus conjugated autologous targets was not detected. It was found that several of these CD8+ clones could suppress IgG production in the presence of rhus antigen. The isolation of these T-cells from peripheral blood several months after rhus dermatitis suggests that these clones may have a role in down regulating delayed hypersensitivity to urushiol.     

Dermatitis from common ivy (Hedera helix L. subsp. helix) in Europe: past,present, and future

Common ivy (Hedera helix subsp. helix) is a well‐known native and ornamental plant in Europe. Reports on contact dermatitis from ivy have regularly appeared since 1899. Recently, it has been suggested that allergic contact dermatitis from the plant may be under‐diagnosed, partly due to lack of commercial patch test allergens. The objective of the article is to present the results of aimed patch testing with the main common ivy allergen, falcarinol, during a 16‐year period and review the newer literature. Consecutive patients tested with falcarinol 0.03% petrolatum from May 1993 to May 2009 were included. Cases published since 1987 were retrieved from the PubMed database. One hundred and twenty‐seven Danish patients were tested with falcarinol and 10 (7.9%) tested positive. Seven were occupationally sensitized. Between 1994 and 2009, 28 new cases of contact dermatitis from ivy were reported, 2 of which were occupational. Only 11 of the 28 patients were tested with pure allergens. Falcarinol is not only widely distributed in the ivy family, but also in the closely related Apiaceae. Sensitization may occur in childhood or in adults pruning ivy plants or handling them in an occupational setting. In view of the ubiquity of falcarinol‐containing plants and the relatively high prevalence of positive reactions in aimed patch testing, falcarinol should be the next plant allergen to be commercially available and included in the plant series worldwide.     

Contact allergy and medicinal herbs

Herbal treatments are becoming increasingly popular, and are often used for internal as well as dermatological conditions, both externally as well as orally. The prevalence of contact sensitization against several plants especially of the Compositae family is quite high in Europe. Sensitization seems to occur relatively frequent with a few species such as arnica, elecampane and tea tree (oil), and occurs rarely with the majority. Testing for plant allergy is problematic because of the limited number of commercially available standardized patch test substances and the danger of active sensitization when testing with plants, parts thereof, or individual extracts. Knowledge about the allergic potential of plants is limited.Although plants are regarded as critical allergens by dermatologists, the number of reported cases of contact dermatitis is relatively small.Many widely used substances are not licensed as drugs or cosmet-ics.While the positive effects are frequently questionable or limited, the side effects are often more evident. Adverse effects of herbal medicines are an important albeit neglected subject in dermatology, which deserves further systematic investigation.     

Compositae dermatitis

Compositae dermatitis is an allergic contact dermatitis. The most important allergens in the Compositae family are sesquiterpene lactones (SL), which are present in the oleoresin fraction of leaf, stem, flower and possibly pollen. Compositae dermatitis is most frequently seen in middle-aged and elderly people in patterns reflecting airborne or direct contact with the allergens. The pattern typically starts in summer and disappears in the autumn or winter. Repeated exposure over many years may lead to a chronic and, at times, a disseminated pattern. Seasonal variation does not occur in occupational Compositae dermatitis. In addition to the classically described airborne pattern of face, 'V' of neck, hands and forearms, hand dermatitis is now recognized to be an equally common presentation. This variability of clinical features, and the frequent occurrence of atopic dermatitis and contact allergy to one or more compounds, highlights the need for routine patch testing with sesquiterpene lactone mix 0.1% (Thermal, Hamburg, Germany), combined with aimed patch testing with Compositae plants and extracts. Avoidance of the plants and plant extracts of this large family can be difficult due to its widespread occurrence in flower, herb and vegetable gardens, urban and rural weed population and native vegetation. Importantly, Compositae plant extracts are present in many cosmetics, shampoos, herbal creams and ingested herbal remedies and tonics.