FS11.5 Toxicodendron dermatitis in the United Kingdom

Abstract

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.