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PubMed2005

[Severe contact-allergy dermatitis due to poison ivy--a plant that is rarely encountered in The Netherlands; a family history].

In successive years, three members of the same family (a man and woman aged 46 years and their son, aged 20) constantly developed severe pruritic, erythematous, vesicular and bullous dermatitis in the spring and summer after working in the garden. Although the findings were consistent with a photophytotoxic dermatitis, the causative plant remained unclear. Oral therapy with high doses ofprednisolone was necessary. When the man travelled to the USA and visited a doctor there, he recognised the symptoms as those of contact dermatitis caused by poison ivy (Toxicodendron radicans), a plant that is found sporadically in the wild state in Europe. Their grandparents had brought the plant back from a trip to the USA and planted it in the garden because of the beautiful fall colours. The family identified the plant via a search on Internet and eliminated it from the garden completely. Since then, the family has no longer suffered from contact-allergy dermatitis.

Adult↗

PubMed1980

GLC analysis of poison ivy and poison oak urushiol components in vegetable oil preparations.

A procedure is described for the analysis of urushiol content of pharmaceutical preparations containing extracts of poison ivy (Toxicodendron radicans) and poison oak (T. diversilobum) in vegetable oils. The procedure involves extraction of the urushiols from the oily solutions using 90% methanol in water followed by GLC analysis of the extracts. Recoveries of both poison ivy and poison oak urushiols from solutions in corn oil, olive oil, sesame seed oil, and cottonseed oil were calculated. Correlation coefficients (r2) ranged from 0.97 to 1.00, and the coefficients of variations ranged from 3.08 to 7.90%.

Catechols↗

PubMed2003

[Allergic contact dermatitis to common ivy (Hedera helix L.)].

Common ivy (Hedera helix L.) is a ubiquitous plant in Europe whose major allergen falcarinol has moderate allergic potential. It is not related to poison ivy (Toxicodendron spp.). There are no cross reactions between the allergens of common ivy (falcarinol) and poison ivy (urushiol). Contact with common ivy or falcarinol may lead to sensitization and then a delayed hypersensitivity reaction. There are only few cases described in the literature. We report on a male hobby gardener with appropriate clinical history and positive patch test. The pathogenic mechanism is a type IV reaction following a sensitization exposure. Gardeners and landscape architects with frequent exposure to common ivy and thus a high risk of sensitization should wear appropriate protective clothing.

Adult↗

PubMed2006

Hahnemann's experiments with 50 millesimal potencies: a further review of his casebooks.

BACKGROUND: A review of Hahnemann's clinical records at the Institute for History of Medicine of the Robert Bosch Foundation in Stuttgart shows that until the end of his life, Hahnemann continued to refine his clinical method, based on clinical cases. His "most perfected method" motivated him to write the sixth edition of the The Organon of the Healing Art, proposing solutions controlling the side effects he observed with repeated doses of homeopathic medicines. Unfortunately, this was published many years posthumously. The sixth edition of The Organon introduced the fifty-millesimal scale. OBJECTIVES: To identify the clinical cases treated with fifty-millesimal potencies and analyze Hahnemann's use of them. RESULTS: 1836 prescriptions of fifty-millesimal potencies were found, between 1837 and 1843 in three phases: initially sporadic; later compared regularly to centesimal dynamizations; and finally systematically. Thirty five medicines were identified in fifty-millesimal prescriptions, seven in potencies higher than 10 and only 3 (Sulphur, Mercurius solubilis and Rhus toxicodendron) used in the 30th degree. This accords with Haehl's information about the remedies in Hahnemann's case of fifty-millesimal potencies. CONCLUSIONS: Hahnemann probably decided to write the sixth edition, in 1840, to incorporate his latest experience with the repetition of potentized doses and periodically modified potencies. He must have revised it after February 1842 to include his latest findings with fifty-millesimal potencies in ascending degrees. Hahnemann's conception about the superiority of the fifty-millesimal in comparison with the centesimal dynamization was based on a significant number of experiments with the two scales.

Germany↗

PubMed2004

Phylogenetic and biogeographic diversification of Rhus (Anacardiaceae) in the Northern Hemisphere.

Sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA, the chloroplast ndhF gene, and chloroplast trnL-F regions (trnL intron, and trnL [UAA] 3' exon-trnF [GAA] intergenic spacer) were used for phylogenetic analyses of Rhus, a genus disjunctly distributed in Asia, Europe, Hawaii, North America, and Northern Central America. Both ITS and cpDNA data sets support the monophyly of Rhus. The monophyly of subgenus Rhus was suggested by the combined cpDNA and ITS data, and largely supported in the cpDNA data except that Rhus microphylla of subgenus Lobadium was nested within it. The monophyly of subgenus Lobadium was strongly supported in the ITS data, whereas the cpDNA data revealed two main clades within the subgenus, which formed a trichotomy with the clade of subgenus Rhus plus R. microphylla. The ITS and cpDNA trees differ in the positions of Rhus michauxii, R. microphylla, and Rhus rubifolia, and hybridization may have caused this discordance. Fossil evidence indicates that Rhus dates back to the early Eocene. The penalized likelihood method was used to estimate divergence times, with fossils of Rhus subgenus Lobadium, Pistacia and Toxicodendron used for age constraints. Rhus diverged from its closest relative at 49.1+/-2.1 million years ago (Ma), the split of subgenus Lobadium and subgenus Rhus was at 38.1+/-3.0 Ma. Rhus most likely migrated from North America into Asia via the Bering Land Bridge during the Late Eocene (33.8+/-3.1 Ma). Rhus coriaria from southern Europe and western Asia diverged from its relatives in eastern Asia at 24.4+/-3.2 Ma. The Hawaiian Rhus sandwicensis diverged from the Asian Rhus chinensis at 13.5+/-3.0 Ma. Subgenus Lobadium was inferred to be of North American origin. Taxa of subgenus Lobadium then migrated southward to Central America. Furthermore, we herein make the following three nomenclatural combinations: (1) Searsia leptodictya (Diels) T. S. Yi, A. J. Miller and J. Wen, comb. nov., (2) Searsia pyroides (A. Rich.) T. S. Yi, A. J. Miller and J. Wen, comb. nov., and (3) Searsia undulata (Jacq.) T. S. Yi, A. J. Miller and J. Wen, because our analyses support the segregation of Searsia from Rhus.

Biological Evolution↗

PubMed1983

Bites, rashes, and itches. How to identify and treat them.

Skin rashes are commonly seen by the primary care physician. The chief cause of contact dermatitis is the plant genus Toxicodendron, but topical medications such as anesthetics, antibiotics, and preservatives also cause this condition. Commonly seen superficial fungal infections include candidiasis and several types of tinea. Microscopic identification of the organism on a potassium hydroxide (KOH) preparation establishes the definitive diagnosis. In addition to occurring in its usual sites, the herpes simplex virus can cause recurrent disease on glabrous skin areas. A positive Tzanck test establishes a diagnosis of herpesvirus infection. Mosquito, flea, and brown recluse spider bites produce diagnostic physical findings. Scabies infestation produces a distinctive eruption, and the diagnosis is made by isolating the mite or its products.

Child↗

PubMed1981

Field recognition of eastern poison oak: with emphasis on plants in Alabama.

Eastern poison oak, Toxicodendron toxicarium, is a nonclimbing shrub whose leaves have three leaflets. The leaflets with their numerous round lobes resemble somewhat the leaves of some oaks in the white oak groups. The plant grows in nutritionally poor, sandy soil, and especially in dry pine-oak woodland. Deposits resembling black enamel paint can often be seen where plants have been injured. During winter, the U- or V-shaped leaf scars, the naked fruit stalks in female plants, and the sparse upright branches all aid in recognition. Other features can be useful in spring and fall. While poison oak and poison ivy are so closely related that the sensitivity of individuals and resulting dermatitis are not markedly different, accurate recognition is important in avoiding contact.

Alabama↗

PubMed1997

Induction of hapten-specific tolerance of human CD8+ urushiol (poison ivy)-reactive T lymphocytes.

The interaction of CD28 with B7 molecules (CD80 or CD86) is an essential second signal for both the activation of CD4+ T cells through the T-cell receptor and the prevention of anergy. We studied the requirement of hapten-specific human CD8+ cells for CD28 co-stimulation in recognition of hapten, and anergy induction. Urushiol, the immunogenic hapten of poison ivy (Toxicodendron radicans), elicits a predominantly CD8+ T-cell response. Autologous PBMC were pre-incubated with urushiol prior to fixation by paraformaldehyde. Fixed antigen-presenting cells were unable to present urushiol to human CD8+ urushiol-specific T cells. Addition of anti-CD28, however, overcame this antigen-presenting defect, enabling CD8+ cells to proliferate. Fixation of antigen-presenting cells prevents upregulation of B7, and addition of anti-CD28 substitutes for this signal. Proliferation of CD8+ T cells in response to urushiol was blocked by CTLA4Ig, a recombinant fusion protein that blocks CD28/B7 interactions. Preincubation of urushiol-specific CD8+ cells with fixed PBMC + urushiol for 7 d induced anergy. Anergic CD8+ cells were viable and able to proliferate in response to IL-2, but not in response to urushiol. Induction of anergy required the presence of urushiol, and pre-incubation with irradiated PBMC + urushiol did not have this effect. It is proposed that anergy was induced by presentation of urushiol by fixed PBMC, in the absence of adequate co-stimulation signals. Induction of anergy by blocking of co-stimulation could potentially induce clinical hyposensitization to haptens.

Abatacept↗

PubMed1990

The use of human T-lymphocyte clones to study T-cell function in allergic contact dermatitis to urushiol.

Allergic contact dermatitis to poison ivy (Toxicodendron radicans) is believed to be mediated by T lymphocytes specific for the hapten urushiol. Activated T lymphocytes may produce pathology by a variety of mechanisms including direct cytotoxicity, production of lymphokines, recruitment of non-specific effector cells, non-specific cytotoxicity, and possibly autologous DR reactivity. The regulation and pathogenesis of this condition was studied by cloning and characterizing urushiol-specific T cells from the peripheral blood of patients with poison ivy dermatitis. Multiple CD8+ (T8+) urushiol-specific clones were derived. All clones that proliferated in response to a crude extract of T. radicans also proliferated in response to purified urushiol. Thus, urushiol appears to be the single immunogenic component of T. radicans resin. Pentadecylcatechol (PDC), which differs from urushiol only in the lack of unsaturated bonds in its lipophilic tail, stimulated only one of seven clones tested. This suggests that the double bonds in the C15 lipophilic tail of urushiol are required for antigenicity. Several of the CD8+ urushiol-specific clone suppressed pokeweed mitogen-induced IgG production in the presence of urushiol. Suppression was triggered specifically by urushiol and required MHC compatibility both for the antigen-presenting cells and the responding B cells. These suppressor clones were isolated from convalescent blood and may represent a mechanism for the termination of an allergic contact dermatitis.

Antigens↗

PubMedDate not supplied

Childhood bullous pemphigoid: report of a case with life-threatening course during homeopathy treatment.

Bullous pemphigoid (BP) is an autoimmune blistering disorder that may very rarely occur in childhood. We describe a 9-month-old child who developed bullous pemphigoid while she was being treated for presumptive atopic eczema with a homeopathic regimen comprising sulfur, mercury, cantharides, and Rhus (Toxicodendron). She had generalized bullae and a progressive worsening of her general condition with asthenia, dehydration, malnutrition. While the role of homeopathy in triggering the disease remains unclear, our observation attests to the potential life-threatening course of childhood BP in instances where appropriate treatment is withheld.

Dermatitis, Atopic↗

PubMed1986

Unusual contact allergens from plants in the family Hydrophyllaceae.

The dermatitic constituents of the glandular hairs of plants in the family Hydrophyllaceae comprise a class of uncommon natural products called "phacelioids". The chemical structures consist of various elaborations of hydroquinone attached to a C10 to C20 prenyl chain. Certain of these compounds are equivalent to the urushiols of Toxicodendron (Rhus) in their capacity to sensitize humans. Although structurally related to the urushiols, the phacelioids do not appear to cross-react in humans either with urushiol, or between phacelioids with different prenyl chains.

Allergens↗

PubMed1992

Heat treatment of Japanese lacquerware renders it hypoallergenic.

Japanese lacquer is made from the sap of the Japanese lacquer tree (Toxicodendron vernicifluum), a member of the Anacardiacae plant family. Objects painted with this material are described collectively as lacquerware. Both fresh lacquer and lacquerware may evoke allergic contact reactions ascribable to the urushiols contained therein. In this study, we have examined the effects of heating on the ability of lacquerware to elicit an allergic contact reaction. Lacquer films prepared with and without heat treatment were tested on urushiol-sensitive subjects. Patch test reactions were strongest to untreated film and decreased with increasing level of heat treatment. Assays for free urushiol in the lacquer films demonstrated that free urushiol content decreased with increasing heat treatment and that urushiols with saturated and monounsaturated alk(en)yl chains predominated.

Adult↗

PubMed1994

Processing of urushiol (poison ivy) hapten by both endogenous and exogenous pathways for presentation to T cells in vitro.

The antigen processing requirements for urushiol, the immunogen of poison ivy (Toxicodendron radicans), were tested by presentation of urushiol to cultured human urushiol-responsive T cells. Urushiol was added to antigen-presenting cells (APC) either before or after fixation with paraformaldehyde. Three distinct routes of antigen processing were detected. CD8+ and CD4+ T cells, which were dependent upon processing, proliferated if urushiol was added to APC before fixation, but did not proliferate when urushiol was added to APC after fixation. Processing of urushiol for presentation to CD8+ T cells was inhibited by azide, monensin, and brefeldin A. This suggests that urushiol was processed by the endogenous pathway. In contrast, presentation of urushiol to CD4+ T cells was inhibited by monensin but not by brefeldin A. This was compatible with antigen processing by the endosomal (exogenous) pathway. Finally, certain CD8+ T cells recognized urushiol in the absence of processing. These cells proliferated in response to APC incubated with urushiol after fixation. Classification of contact allergens by antigen processing pathway may predict the relative roles of CD4+ and CD8+ cells in the immunopathogensis of allergic contact dermatitis.

Anti-Bacterial Agents↗

PubMed1999

[Prevention of allergy by protective skin creams: possibilities and limits].

Despite promising efficacy data for protective creams and many scientifically proven advances that have been achieved concerning the prevention of irritative contact dermatitis, protection against sensitising substances remains a particular problem due to the minimal amounts of allergen that trigger allergic contact dermatitis. Therefore, specific allergen-blocking substances have been tested which are designed to prevent sensitising processes and in particular avoid occurrence of contact dermatitis in already sensitised individuals. In this review, we present the results of current studies mainly focussed on preventing occupational contact dermatitis caused by metal salts, using different chelating agents. In the United States allergic contact dermatitis is often due to strongly sensitising plant allergens of Toxicodendron species, a factor of importance in outdoor professions. Therefore, attempts have been made to use linoleic acid dimers and organoclay materials such as quaternium-18 bentonite for prophylaxis in topical treatments. Most studies investigate effectiveness against experimentally induced allergic contact dermatitis in sensitised volunteers using standardised allergen extracts. Although several preparations showed some benefit by possibly preventing certain quantities of allergen from penetrating the epidermis, further effort will be required before sufficient protective creams with allergen-blocking properties are available for workplaces.

Adrenal Cortex Hormones↗

PubMed2001

Adverse and beneficial effects of plant extracts on skin and skin disorders.

Plants are of relevance to dermatology for both their adverse and beneficial effects on skin and skin disorders respectively. Virtually all cultures worldwide have relied historically, or continue to rely on medicinal plants for primary health care. Approximately one-third of all traditional medicines are for treatment of wounds or skin disorders, compared to only 1-3% of modern drugs. The use of such medicinal plant extracts for the treatment of skin disorders arguably has been based largely on historical/anecdotal evidence, since there has been relatively little data available in the scientific literature, particularly with regard to the efficacy of plant extracts in controlled clinical trials. In this article therefore, adverse and beneficial aspects of medicinal plants relating to skin and skin disorders have been reviewed, based on recently available information from the peer-reviewed scientific literature. Beneficial aspects of medicinal plants on skin include: healing of wounds and burn injuries (especially Aloe vera); antifungal, antiviral, antibacterial and acaricidal activity against skin infections such as acne, herpes and scabies (especially tea tree (Melaleuca alternifolia) oil); activity against inflammatory/immune disorders affecting skin (e.g. psoriasis); and anti-tumour promoting activity against skin cancer (identified using chemically-induced two-stage carcinogenesis in mice). Adverse effects of plants on skin reviewed include: irritant contact dermatitis caused mechanically (spines, irritant hairs) or by irritant chemicals in plant sap (especially members of the Ranunculaceae, Euphorbiaceae and Compositae plant families); phytophotodermatitis resulting from skin contamination by plants containing furocoumarins, and subsequent exposure to UV light (notably members of the Umbelliferae and Rutaceae plant families); and immediate (type I) or delayed hypersensitivity contact reactions mediated by the immune system in individuals sensitized to plants or plant products (e.g. peanut allergy, poison ivy (Toxicodendron) poisoning).

Burns↗

PubMed2004

[Niche characteristics of plant populations in Quercus aliena var. acuteserrata stands in Qinling Mountains].

Based on the data collected from 31 plots and using Levins, Hurlbert and Pianka formulas, this paper calculated and analyzed the niche breadths and overlaps of 24 tree and 29 shrub populations in Quercus aliena var. acuteserrata stands in Mt. Qinling, Shaanxi. The results showed that the Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata , Pinus armandi, Toxicodendron vernicifluum, Populus davidiana and Pinus tabulaeformis in arbor layer were 3.695, 1.695, 1.325, 0.840, 0.702 and 0.036, 0.299, 0.568, 1.721, 2.701 respectively, and those of Corrylus heterophylla, Lespedeza formosa and Smilax vaginata in shrub layer were 1.833, 1.466, 0.984 and 0.111, 0.300, 0.594, respectively. In general, the niche overlaps between the species with bigger niche breadth and other species were higher, and those of the species having similar environmental requirements were also higher.

Biodiversity↗

PubMed1991

Philodendron-induced dermatitis: report of cases and review of the literature.

Plants of the genus Philodendron, and the family Araceae, were reported as causing dermatitis as early as 1923. The allergenic compounds in philodendrons are resorcinols, which share common chemical side chains with the allergenic catechols of Toxicodendron members of the family Anacardiaceae. I report here two cases of allergic contact dermatitis to Philodendron species commonly found in the Hawaiian islands. Philodendron dermatitis, however, is not confined to tropical or subtropical areas. Exposure may occur in nursery workers in temperate climates and in the home environment worldwide.

Acute Disease↗

PubMed1998

Systemic contact dermatitis to raw cashew nuts in a pesto sauce.

Systemic contact dermatitis from the cashew nut shell oil resorcinol allergens cardol and anacardic acid is recognized clinically as a dermatitis with flexural accentuation, typically distributed on the extremities, groin, and buttocks, and occurring generally 1 to 3 days after ingestion of raw cashew nuts contaminated with allergenic oil. We report a case of systemic contact dermatitis to raw cashew nuts, an atypical and unexpected ingredient flavoring an imported pesto sauce. Plants with allergens that potentially cross-react with poison ivy and other Toxicodendrons, and the concepts of systemic contact dermatitis and hyposensitization are reviewed.

Allergens↗