Plant Dermatitis.

Plant dermatitis is a common pathology that plagues those who work and recreate in the North American outdoors. The most common plant family to cause dermatitis is the Toxicodendron genus, which includes the plants known by the common names of poison ivy, poison oak, and poison sumac. While mortality is usually quite low for this pathology, the incidence and prevalence of the disease leads to substantial healthcare burden and financial implications across the population. The mainstays of treatment have focused on prevention, corticosteroids, and antihistamines.

Poison Ivy, Poison Oak, and Poison Sumac.

This JAMA Patient Page describes allergic skin reactions from contact with poison ivy, poison oak, and poison sumac plants, and how to treat rashes caused by these plants.

Plant Dermatitis: More Than Just Poison Ivy.

Plants can cause allergic contact dermatitis (ACD), mechanical irritant contact dermatitis, chemical irritant contact dermatitis, light-mediated dermatitis, and pseudophytodermatitis. Allergic contact dermatitis to chemicals in the Toxicodendron genus, which includes poison ivy, poison oak, and poison sumac, is the most common cause of plant ACD; however, many other plants, such as Compositae, Alstroemeriaceae, and Rutaceae plants also are important causes of dermatitis. In individuals with recurrent ACD from plants other than Toxicodendron, patch testing can be used to identify the source of allergic reactions to plant species. This article provides an overview of the various plant dermatoses, common culprits of plant dermatitis, and diagnostic and therapeutic options for plant dermatoses.

Heracleum mantegazzianum and Toxicodendron succedaneum: plants of human health significance in New Zealand and the National Pest Plant Accord.

New Zealand's National Pest Plant Accord (NPPA) is a voluntary and cooperative agreement between industry, regional councils, and central government departments with biosecurity responsibilities (primarily the Ministry of Agriculture and Forestry and the Department of Conservation). Plant species included in the NPPA are declared unwanted organisms under the Biosecurity Act 1993, which prevents their sale, propagation, or distribution across the country. Although MAF Biosecurity New Zealand (the lead agency in New Zealand's biosecurity system) has evaluated the potential human health impacts of 202 species considered for inclusion in the NPPA, two species were examined primarily due to their significance to human health: Heracleum mantegazzianum (giant hogweed, cow parsnip, wild parsnip) and Toxicodendron succedaneum (rhus tree, wax tree, Japanese wax tree). As a result of this process, H. mantegazzianum has been listed in the NPPA. In contrast, T. succedaneum was not included in the NPPA, as the latter was deemed to be an inappropriate mechanism for its control. In this article the NPPA process is outlined, and the adverse impacts on human health of these two species are discussed--including symptoms, treatment, and possible management measures.

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.

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.

[Contact allergy caused by poison ivy (Toxicodendron spp]. / 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.

Single dose parenteral hyposensitization to poison ivy urushiol in guinea pigs.

Studies were carried out in guinea pigs to evaluate the potential for single dose hyposensitization to poison ivy urushiol dermatitis. Sensitization was induced by topical application of 1 mg of poison ivy urushiol to the back of the neck. In the first series of studies, three different analogs of poison ivy urushiol were studied: 1) a mixture of pentadecyl and heptadecyl catechols (PDC/HDC), the saturated side chain analog of the natural urushiol mixture; 2) a mixture of the diacetate esters of PDC and HDC (PDC/HDC Ac), the esterified form of the saturated sidechain analogs; 3) 2-n-pentadecyl hydroquinone diacetate (HQ Ac). Each of these compounds was administered as 5 mg of the free catechol i.m. each week for three weeks. A vehicle group received only corn oil injections. Reactivity to poison ivy urushiol (PIU) challenge was evaluated in skin tests at 1 and 5 weeks post-treatment. PDC/HDC Ac induced a marked reduction in both the incidence and the severity of lesions induced by PIU at both 1 and at 5 weeks post-treatment. Other analogs were ineffective at 5 weeks post-treatment, and were less effective than PDC/HDC Ac at 1 week post-treatment. In a second series of experiments, the efficacy of PDC/HDC Ac was evaluated in both single and multiple dose regiments. One treatment group received 5 mg of PDC/HDC Ac intramuscularly each week for 4 weeks, while another treatment group received a single dose of 20 mg PDC/HDC Ac i.m. Corresponding vehicle control groups were also included. At 1 week post-treatment in the single dose group, the PDC/HDC Ac was only modestly effective, with some reduction of severity of lesions at the higher challenge doses of PIU. However, at 4 and 7 weeks post-treatment, both the incidence and the severity of the lesions at all challenge doses were reduced. In the multiple dose group, the incidence and severity of lesions are reduced at 1 week and 4 weeks post-treatment (4 weeks and 7 weeks after the initial dose) but were not significantly different from the single dose group. These findings indicate that the diacetate ester of PDC/HDC is an effective hyposensitizer to poison ivy urushiol, and that this hyposensitization can be reasonably accomplished in a single dose treatment regimen.

Poison ivy dermatitis. Nuances in treatment.

Acute allergic contact dermatitis due to poison ivy or poison oak is a common presenting complaint in the practices of many primary care physicians. While the clinical features are well described, reported treatment regimens vary in both topical and systemic therapies. We review herein the variability of presenting morphologic features of the disease and common treatment regimens, with attention given to complications of therapy. We also comment on the correct botanical designation, incidence, and immune mechanisms of the disease state and review measures to avoid allergic contact dermatitis due to poison ivy and poison oak.

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.

Acupuncture for poison ivy contact dermatitis. A clinical case report.

Poison ivy contact dermatitis is fairly common in the suburbia of this country among amateur gardeners and children. It commonly inflicts its poison on the exposed parts of the limbs. The vesicular or bullous skin lesions are quite disturbingly itchy. Scratching the itchy lesions often spreads the condition by transplanting the remanent resinous toxin to other parts of the body. Though they are usually self-limiting, the intense itch is the main motivation for a patient to seek medical care. The conventional treatment is basically ineffective. During the summer of 1987 we treated four such cases of dermatitis with acupuncture upon their request to mollify their unbearable itch. They originally consulted with us for other problems. There were three males and one female. Their ages were between 29 and 63. Three cases were relatively mild and the fourth one was fairly severe. In the milder cases, their itch subsided in a few hours and skin lesions were healed in about two days after one treatment. In the severe case the itch subsided in about two days and most of the skin lesions dried up in four days after the first treatment and were healed almost completely after three sessions of acupuncture treatment. The plausible anti-inflammatory mechanism of acupuncture with the involvement of ACTH and/or cortisol was discussed.

Oral hyposensitization to poison ivy and poison oak.

We evaluated the safety and efficacy of a 1:1 mixture of pentadecylcatechol (PDC) and heptadecylcatechol (HDC) diacetate in reducing hypersensitivity to poison ivy and poison oak. The study was double-blind, parallel, randomized, and placebo controlled. The 44 subjects receiving the active drug ingested a cumulative dose of 306.5 mg over a five-week period. Subsequently, 14 patients were continued on a maintenance phase, ingesting an additional 960 mg of drug. The PDC-HDC diacetate was well tolerated, with no significant side effects. Evaluation of efficacy compared poststudy and prestudy reactions to patch tests using urushiol in doses of 0.025, 0.05, 0.125, 0.25, and 0.5 micrograms applied to the forearm. The results indicated that the induction phase as well as the maintenance phase did not induce a statistically significant hyposensitivity to urushiol, and we were thus unable to decrease sensitivity to poison ivy and poison oak in humans using orally ingested PDC-HDC diacetate.