Safety & Health Assessment & Research for Prevention (SHARP) Research for Safe Work
Reprinted with permission from the American Academy of Dermatology. All rights reserved. Please note that the slides are very large JPEG files that will take up to 6.5 minutes to view or download using a 28.8 kbps modem.
Allergic Contact Dermatitis
Allergic contact dermatitis requires previous sensitization to low molecular weight compounds in a plant. Not everyone develops an allergic reaction to these compounds. The most common plant causing this reaction is poison oak or ivy. The large family of plants, Compositae, contain chemicals called sesquiterpene lactones, which are sensitizers and irritants. Most of these rashes are chronic, eczematous rashes as compared to the severe blisters that develop from contact with the poison oak or ivy plants. Allergic contact dermatitis is the least common type of plant reaction except for problems with poison oak or ivy.
Slide 21
The poison ivy plant (Toxicodendron radicans) has leaves grouped in three and can grow vine‑like up the trunks of trees. The leaves of the Western shrub‑like poison oak plant (Toxicodendron diversibolum) are also grouped in three but are shorter than poison ivy and are slightly lobed on the edge resembling oak‑shaped leaves.

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Slide 22
The ginkyo tree (Ginkyo biloba) has distinctive fan-shaped leaves. The allergen (ginkgolic acid) is similar to urushiol oil.

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Slide 23
The ginkyo tree (Ginkyo biloba) allergen (ginkgolic acid) is present in the ovule of the female tree.

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Slide 24
The artichoke (Cynara scolymus) has an edible flowering head. Allergic reactions to the sesquiterpene lactone compound in the stems and roots can be seen in pickers, florists and produce workers in groceries.

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Slide 25
Yarrow (Achilles millefolium).

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