Poison oak

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Poison oak
\n\n\n\n\n\n\n\n\n : Plantae : Magnoliophyta : Magnoliopsida : Sapindales : Anacardiaceae : Toxicodendron : Diversilobum \n
Binomial name
Toxicodendron diversilobum

Western poison oak (Toxicodendron diversilobum or, previously, Rhus diversiloba) is found only on the Pacific Coast of the United States and of Canada. It is extremely common in that region, where it is the predominant species of the genus. Poison oak is extremely variable in growth habit and leaf appearance. It grows as a dense shrub in open sunlight, or as a climbing vine in shaded areas. Like poison ivy, it reproduces by creeping rootstocks or by seeds. The leaves are divided into 3 leaflets, 3½ to 10 centimeters long, with scalloped, toothed, or lobed edges. Western Poison Oak is found only on the Pacific Coast, where it is common, and ranges from Southern Canada to Baja California. It is California's most prevalent woody shrub and is often found in oak woodlands. In comparison to true oaks, the leaves will tend to be rather more glossy.\n

Toxin

\nPoison oak leaves and twigs have a surface oil that is an irritant. Depending upon individual suceptability and exposure, the symptoms can range from trivial to life threatening. The common effect is an irritating itchy rash. Before the oil is removed, it can be transferred from one part of the body to another, from one person to another by contact or by transfer through an object (such as an automobile seat belt), from a pet to a person, or from clothing to skin when clothes are prepared for washing. If exposed, the recommended immediate treatment is to wash the exposed area with strong soap and cold water. (Warm water will tend to open pores on the skin and will lead to deeper irritation.) After the oil has been removed, the poison oak cannot be spread by contact with an affected area or by scratching. However, scratching can open the skin especially in cases with significant blistering, making it possible for the skin to become infected by opportunisitic bacteria (known as a secondary infection). Mild cases of poison oak rash are treated with calamine lotion and other drug store aids while severe cases may require medical treatment and even hospitalization. Inhalation of smoke from burning poison oak can result in life-threatening lung damage. (There is an extensive section concerning treatment within the poison ivy article.)

External links

\nTreatment discussion\nHistory, description, and treatment\n