Hyposensitization to poison ivy after working in a cashew nut shell oil processing factory

19 adults were patch tested to urushiol, the allergen in poison ivy/oak, to determine their sensitivity to this allergen after working in a cashew nut shell oil (CNSO) processing plant. The cashew nut tree and poison ivy/oak are in the same botanical family. Anacardiaceae, and they share similar chemicals which cause allergic contact dermatitis. 13 of the 19 workers had a preemployment history of poison ivy sensitivity, with 10 developing CNSO dermatitis. After working in this factory for several months, 9 of the 13 noticed a decreased sensitivity or no sensitivity to poison ivy/oak. When tested to urushiol extract, only 3 reacted positively, 2 minimally. These results imply that hyposensitization to poison ivy/oak occurred in these employees after development of hardening to cashew nut shell oil.     

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.     

Toxicodendron dermatitis in the UK

BACKGROUND: We present two cases of Toxicodendron dermatitis, one acquired in the United States but presenting in the United Kingdom (UK), the other a recurrent dermatitis following importation of the plant 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. CONCLUSIONS: 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 Europe and it is therefore possible for an individual to be sensitised and subsequently to develop the rash without leaving the continent.     

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.     

Age differences in poison ivy dermatitis

In both man and animals, cell-mediated immunity diminishes with advanced age, Because poison ivy is a very common allergy, we evaluated age-associated differences in the contact allergic reaction to Rhus. Oleoresin patch tests were applied to two age cohorts (18-25 versus 65-84) each of 14 healthy white subjects. In the elderly, the allergic reaction developed more slowly, the inflammatory response at peak was greatly diminished and the dermatitis lasted longer and seemed to be more pruritic.     

A potent contact allergen of Phacelia (Hydrophyllaceae)

The major contact allergen of Phacelia crenulata (Hydrophyllaceae) has been identified as geranylhydroquinone. A maximization test of geranylhydroquinone showed this to be a potent sensitizer comparable in degree to poison oak/ivy urushiol. Comparative patch testing on humans with urushiol established that the Phacelia allergen does not cross-react with poison oak or ivy.     

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.     

Erythema multiforme‐like eruption associated with plant‐induced allergic contact dermatitis in a pediatric patient: A case report

An 11‐year‐old boy presented to the emergency department 5 days after playing in the forest. His initial eruption, consistent with allergic contact dermatitis to poison ivy, progressed into target lesions involving his extremities, palms, upper trunk, and face, consistent with an erythema multiforme‐like eruption. This report details the case and reviews the literature concerning this atypical and potentially underreported complication of plant‐induced allergic contact dermatitis.     

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.     

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.     

Poison ivy dermatitis

Eruptions caused by poison ivy (see Cover) and related plants are almost always a form of allergic contact dermatitis. Usually they can be readily recognized because of their characteristic streak- or line-like appearance. They usually clear within one to three weeks unless there is continued exposure to the allergen. Local treatment suffices in mild to moderate cases, but in more severe cases systemic corticosteroids can be added.     

Poison ivy dermatitis

Eruptions caused by poison ivy and related plants are almost always a form of allergic contact dermatitis. Usually they can be readily recognized because of their characteristic streak-or-line-like appearance. They usually clear within one to three weeks unless there is continued exposure to the allergen. Local treatment suffices in mild to moderate cases, but in more severe cases systemic corticosteroids can be added.     

Leaves of three, let them be: if it were only that easy!

Humans of all races and skin color are susceptible and uniquely sensitive to poison ivy, oak, and sumac. Contact with the plant oil, urushiol, found not only in the leaves but in the stems and roots, results in an allergic contact dermatitis in 50% to 60% of people. Clinical manifestations, differential diagnosis, complications, and treatments are discussed, with a special emphasis on the pediatric population.     

Hypersensitivity reaction to the ingestion of mango flesh

A 42-year-old woman presented with a hypersensitivity reaction after the ingestion of a small amount of fresh mango gelato. She developed itchy palpable purpuric lesions over her arms, legs, neck and abdomen 4 days after ingestion. The lesions persisted for 5 weeks despite treatment with betamethasone-17 valerate 0.05% ointment and avoidance of mango. Resolution of these lesions was eventually achieved with continuing treatment. The patient denied any prior contact with mango skin but had experienced previous sensitizing reactions to mango flesh. Patch testing was strongly positive to mango skin and mango flesh. Skin-prick testing was negative. This case describes a systemic contact dermatitis to mango flesh, an entity less common than allergic contact 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.     

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.     

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.     

A single accidental exposure may result in a chemical burn, primary sensitization and allergic contact dermatitis

It is known from experimental studies that antigenic potency and the concentration of antigen determine whether exposure to an antigen will result in sensitization. A single accidental exposure to concentrated antigen may therefore induce primary sensitization. The purpose of this report was to collect clinical cases in which a single exposure had resulted in contact dermatitis suspected to be allergic. Only patients without previous relevant skin symptoms were included. Patch testing was used to demonstrate sensitization. 6 patients developed occupational allergic contact dermatitis from accidental exposure. Patch testing revealed allergy to diglycidylether of bisphenol A epoxy resin, poly functional aziridine hardener, methyl acrylate, phenol-formaldehyde resin, and methylchloroisothiazolinone/methylisothiazolinone (Kathon LX), respectively. Furthermore, 2 patients developed allergic contact dermatitis from their first exposure to tear gas chemicals, namely omega-chloroacetophenone and ortho-chlorobenzylidene malonitrile. A single exposure can therefore induce both sensitization and subsequent allergic contact dermatitis without further exposure. The allergens described must be considered strong allergens. The skin should immediately be cleaned if an accidental splash with such an allergen has taken place.     

Mango dermatitis: Allergic contact dermatitis to Mangifera indica

‘Mango Dermatitis’ is the common term given to allergic contact dermatitis to the sap or skin of the fruit of Mangifera indica. Four patients presented with urticaria and eczematous rash following exposure to mangoes or the trees. Patch testing with diluted sap, crushed leaf, crushed stem and fruit skin was strongly positive.     

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.