The three most common toxic plants that campers are likely to encounter are poison ivy, poison oak and poison sumac. Any one of these can cause a painful, itchy rash.
Poison ivy is probably the most common of the three, since it grows throughout most of North America. Shrubs can be as tall as four feet (1.2m), but it is frequently found as ground cover between 4-10 inches (10-25cm) high. It rarely grows above 5,000 feet, but most campsites are below this elevation.
There’s an old saying ‘leaves of three, let it be’ that makes for a good start on identification. The leaves tend to be a dark, dull green but can be purplish at certain times of the year.
Poison oak also has multi-lobed leaves, with fuzzy fruit on the branches. Sometimes the leaves are scalloped around the edge and can be wrinkled rather than smooth as poison ivy leaves are. Three lobes are more common, but five lobed leaves exist as well.
Poison oak grows in sandy soils from southern New Jersey to Florida, but occur in western parts of the U.S. too, such as Kansas, Oklahoma and Texas. The range extends north to the Sierra Nevada all the way up to southwestern British Columbia in Canada and as far south as northern Baja California in Mexico. Some types are found in Washington, in the Columbia River gorge, Oregon and Nevada.
Poison ivy is more common in the east, poison oak in the west and south.
Poison sumac is the least widespread, since it prefers very wet soils such as swamps and peat bogs. The leaves are bluish green, sometimes with red tips or tints. The berries on the bush are cream colored. Though less common, it is the most toxic of the three.
All of them produce urushiol, which is the material that sticks to the skin and produces the unpleasant rash. One particular problem with contact is that since urushiol is oily it can easily be spread to parts of the face, hands and elsewhere by casual brushing. The oil tends to stick to parts it contacts and then stays there, where it quickly binds with skin cells.
The rash can range from mild to severe and cortisol creams are usually used to treat the symptoms. The first step to treating it, once you know you’ve made contact, is to avoid spreading it. Don’t touch your face or other parts of the body.
Washing thoroughly with soap and water helps, but once contact has been made some amount of effect is almost inevitable. Fifteen minutes after contact, washing has minimal effect, since the urushiol has already bonded to the skin. There are a fortunate percentage (around 15%) of individuals who are immune to the effects. There’s no vaccine and extreme cases can lead to blistering and a burning sensation.
Apply a spray or cream to treat the effects and avoid scratching, no matter how great the temptation. That will only make it worse. The effects take about two weeks to fully wear off, but if treated the itching will subside in a few days to a week.
Avoidance is the best policy.