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Grevillea 'Robyn Gordon' is an Australian hybrid plant which may cause allergic contact dermatitis. Over the past 8 years, it has been planted extensively in Australia and is now being exported to the United States and other Western countries. Recently, an 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 pentadecyleatechol, is closely linked in chemical structure to 5-pentadecylresorcinol, present in Grevillea 'Robin Gordon' with tridecylresorcinol produced positive reactions, thus implicating the sensitizing rô of long chain alkyl resorcinols in Grevillea 'Robyn Gordon' allergy. There is a likelihood that this sensitizing potential extends to other plants of the Grevillea genus, Grevillea robusta. With the spread of Grevillea 'Robyn Gordon' to other markets, this problem will become increasingly common. [ABSTRACT FROM AUTHOR]

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 C[subm] to C[subw] prenyl chain. Certain of these compounds are equivalent to the urushiols of Toxicodendron (Rhus) 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 phenyl chains. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

American folklore is replete with remedies for Toxicodendron dermatitis which have been used. A common folk remedy used by butanists, naturalists and even physicians employs Impatiens, commonly called touch-me-not or jewelweed. Results of a study done to compare the effectiveness of water and jewelweed in preventing poison ivy dermatitis were conducted. Two dermatitis affected areas were used as controls and the other two affected areas were treated immediately with either water or sap from Impariens bioflora.

North Queensland, Queensland, forest officers were unanimous in stating that the wood of Blepharocarya involucrigera was poisonous if rubbed on the skin. The family of Blepharocaryaceae Airy Shaw differs in having opposite pinnate leaves and a highly peculiar female inflorescence. A total of 39 individuals known to be contact sensitive to Toxicodendron syn. Rhus were patch-tested to dried leaves of Blepharocarya involucrigera. Twelve males and 24 females showed negative patch test reactions to the leaves suggesting absence of pentadecyl-catechols from the leaves of Blepharocarya involucrigera.

This article discusses medical cases related to allergic contact dermatitis from toxicodendron succedaneum. More than 140 cases of phytodermatitis were reviewed. Although in most instances toxicodendron succedaneum was considered most likely responsible, definite identification was made in only 92 patients. Younger patients presented with facial dermatitis, reflecting contact while playing under trees. Allergy to anacardiacease shrubs and trees is well recognized. Toxicodendron succedaneum causes more than 2 million cases of allergic contact dermatitis in the U.S. every year.

The study design was chosen to mimic a potential clinical situation in which a patient, known to have toxicodendron sensitivity, would begin taking pentoxifylline on the morning of a planned outdoor activity that would place them at risk of exposure later that day. In this study, the short time of pretreatment with pentoxifylline did not appear to influence reactivity to untshiol under controlled laboratory exposure. Whether longer pretreatment, different dosage, or different allergen would yield a different result is not known. However, the laboratory exposure to urushiol, used to evaluate pentoxifylline in this report, was significantly abrogated by a topical barrier lotion, suggesting that allergen exposure was not so overwhelming that it could not be blocked by an effective prophylactic agent.

The article presents information on cases of allergic contact dermatitis in families. Contact dermatitis occurring simultaneously in more than one member of a family has rarely been reported. This article reports about four families in whom allergic contact dermatitis developed in more than one family member at the same time. All four cases presented with allergic contact dermatitis from Toxicodendron succedaneum. The first case is of a family were, three siblings, aged seven to nine years, were trampolining under a Rhus tree in the garden. Within two days, all three presented with periorbital oedema and streaky vesicle formation on the face, requiring systemic corticosteroids.

The effectiveness of hypersensitization therapy using commercial poison ivy⁄oak extracts has been questioned by the U.S. Food and Drug Administration, as of October 1, 1990. The concentration of injectable products is extremely important as deaths have occurred from natural products used for this purpose and local reactions at injection sites make injectable hyposensitization less desirable than the oral method. All the commercial oral and injectable products still available by reverse phase high performance liquid chromatography were analysed.

The article focuses on the discovery that leaves of Ginkgo biloba are not allergic for toxicodendron-sensitive subjects. The fruit pulp of the Ginkgo tree of the Maiden Hair family is known to be allergenic and to cause contact reactions. The author carried out many tests with dried leaves of compositae plant and found them to retain their allergenicity. Some experts made an important observation that plant material of Phacelia loses allergenicity on drying owing to oxidation of allergens to a non-reactive compound.

Many consider the reaction time in contact dermatitis to be 12-96 hours and some consider reactions at 96 hours or beyond to be due to sensitization produced at the time of testing. In a series of patch tests conducted using poison ivy oleoresin on human skin showed that skin reactions were approximately equal in intensity at 2 days after their appearance. These reaction times were both less than and greater than those commonly accepted. It was seen that the site of exposure is probably an important factor in determining the reaction time. Certainly, not all reactions after 96 hours are due to test sensitization.