Topical prevention of poison ivy/oak dermatitis

An organoclay preparation was evaluated for topical protection against experimental poison ivy/oak in a rigorous double-blind study. By direct comparison with the same subject, it proved more effective than comparable preparations of bentonite, kaolin, or silicone in 16 of 17 trials. When evaluated globally against control responses to urushiol the organoclay preparation gave 95.3% protection against topical urushiol applications, ranging from 4.75 to 0.0475 nmol. Bentonite, kaolin, and silicone gave 29.6%, 37.9%, and 32.9% protection, respectively, in the same system. We conclude that organoclay is an effective topical protectant against experimental poison ivy/oak dermatitis, and deserves further clinical evaluation.     

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.     

Dermatitis artefacta induced in a patient by one of her multiple personalities

A young woman suffered for 5 weeks with an inexplicable, severe dermatitis limited to her left arm. During hospitalization it was found that she had multiple personalities, one of whom had been applying the leaves of the poison ivy plant each night to her left arm, using 'his' gloved right hand. The factitial nature of the dermatitis was further documented by the fact that when the 'responsible personality' was cut off from supplies of poison ivy in the hospital, 'he' produced factitious haematomas by trauma to her left hand. Although this appears to be the first report of dermatitis artefacta associated with the multiple personality disorder, it is suggested that psychiatric study of other dermatitis artefacta patients might reveal the presence of unsuspected occult multiple personalities, responsible for skin lesions that patients cannot explain.     

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.     

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.     

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.     

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.     

Induction of tolerance to poison ivy urushiol in the guinea pig by epicutaneous application of the structural analog 5-methyl-3-n-pentadecylcatechol

Previous studies have established that epicutaneous application of 5-methyl-3-n-pentadecylcatechol (5-Me-PDC), a synthetic analog of a poison ivy urushiol component, leads to immune tolerance to 3-n-pentadecylcatechol (PDC) in mice. The induction of tolerance by 5-Me-PDC may be mediated by a protein conjugate formed via selective reaction of thiol nucleophiles present on the carrier macromolecule with the corresponding o-quinone derived from the parent catechol. In order to examine further the tolerogenic properties of 5-Me-PDC, we have extended our studies to the guinea pig, the generally accepted experimental species for the study of contact allergy. The results have established that specific immune tolerance to poison ivy urushiol is induced following 2 epicutaneous applications of the PDC analog. Furthermore, we were able to show that the treated animals remained tolerant for at least 6 weeks, a period of time comparable to that observed following the intravenous administration of the O,O-bis-acetyl derivative of PDC. The data point to the possibility of developing a therapeutically effective topical tolerogen for poison ivy contact dermatitis.     

Toxische Kontaktdermatitis auf Poison Ivy in einem Privatgarten in Deutschland

A couple suffered for 5 years from recurrent eruptions with vesicles and bullae after contact with an unknown "climbing weed" in their private garden in Germany. After this plant was identified as poison ivy and eradicated, their skin problems were solved. This is the first report of poison ivy in this setting. Urushiols in poison ivy are not only strong allergens but also potent irritants. Negative patch tests in the husband suggest that the bullous dermatitis was a toxic reaction.     

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.     

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.     

Basophil degranulation induced by oral poison ivy antigen.

Seven subjects shown by patch test to be sensitive to poison ivy oleoresin were challenged with graded oral doses of ivy extract. In each instance the circulating basophil leukocytes showed significant degranulation within one hour of challenge. This finding was interpreted as evidence of the presence of immediate-type circulating antibody to ivy antigen in these subjects. No drop in the absolute basophil count was noted, but with higher oral doses the degranulation persisted for several days. Thirteen control subjects showed no change in the basophil morphology or count, indicating that the resin at these levels was not toxic to this cell. All but one of the sensitive subjects showed objective patch test evidence of hyposensitization following the intensive three-week course of oral poison ivy antigen.     

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.     

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.     

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.     

Microbiology of infected poison ivy dermatitis

We report the aerobic and anaerobic microbiology of secondarily infected poison ivy dermatitis. The study involved retrospective review of clinical and microbiology laboratory records of patients with secondarily infected poison ivy lesions. Bacterial growth was noted in 33 specimens. Aerobic or facultative anaerobic bacteria only were present in 18 (55%) patients, anaerobic bacteria only in seven (21%), and mixed anaerobic-aerobic bacteria in eight (24%). Forty-five isolates were recovered (1.4 per specimen): 27 aerobic or facultative anaerobic bacteria, and 18 strict anaerobes. The predominant aerobic and facultative anaerobic bacteria were Staphylococcus aureus (13 isolates) and group A beta-haemolytic streptococci (six). The predominant anaerobes were Peptostreptococcus spp. (seven isolates), pigmented Prevotella and Porphyromonas spp. (four) and Fusobacterium spp. (two). Single bacterial isolates were recovered in 18 (55%) patients, eight of which were S. aureus. Nineteen of the organisms isolated from 16 (48%) patients produced the enzyme beta-lactamase. Organisms that resided in the mucous membranes close to the lesions predominated in those infections. Enteric gram-negative rods and Bacteroides fragilis group predominated in leg and buttock lesions. Group A beta-haemolytic streptococci, pigmented Prevotella and Porphyromonas and Fusobacterium spp. were most frequently recovered from lesions of the finger, face and neck. The polymicrobial aetiology of secondarily infected poison ivy lesions, and the association of bacterial flora with the anatomical site of the lesions, are demonstrated.     

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.     

Assessment of the ability of the topical skin protectant (TSP) to protect against contact dermatitis to urushiol (Rhus) antigen.

BACKGROUND: Military personnel have a need for effective protection against cutaneous exposure to chemical warfare agents (CWA). Topical Skin Protectant (TSP) is being developed to supplement chemical warfare protective garments. TSP protects against CWA exposure in animals, but does it work for humans? Because humans should not be tested with live CWA, urushiol (poison ivy) extract was used as a surrogate substance in place of CWA for human efficacy testing of TSP. OBJECTIVE: Determine whether TSP protects human skin against experimentally-induced urushiol dermatitis. METHODS: Open urushiol patch testing of 50 rhus-sensitive subjects comparing the 96-hour dermatitis severity scores between TSP protected and TSP unprotected sites. There were 4 paired sites (i.e., protected versus unprotected) per subject. Test sites were scored using a 9-point dermatitis scale of 0.0 to 4.0 (using 0.5 increments). RESULTS: Analysis of variance of the dermatitis scores from 192 paired sites on 48 evaluable subjects showed that TSP protected sites had mean dermatitis scores about 2 points lower than TSP unprotected sites (P <.001). CONCLUSION: Although this study does not provide direct scientific evidence that TSP protects humans against the percutaneous absorption of CWA, it does provide circumstantial evidence that this is the case. The fact that TSP is so highly effective against a lipophilic substance like urushiol and that most common vesicant CWAs are lipophilic and are weaponized in oleaginous vehicles, makes the effectiveness of TSP in preventing absorption and dermatitis from CWA seem likely.     

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.     

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.