Poison Ivy -- the basics

Poison ivy (click for photo example) are all members of the Anacardiaceae family of plants. The Toxicodendron (“means poisonous tree”) genus of plants causes more contact dermatitis than all other causes combined. Ten to fifty million Americans develop allergic contact dermatitis to a Toxicodendron annually. In one study 10% of all occupational injuries among seasonal farm, workers in PA and NY were due to poison ivy contact. The genus/species names are as follows:

• common or northern poison ivy (Toxicodendron radicans)

• western poison ivy (Toxicodendron rydbergii)

• eastern poison oak (Toxicodendron toxicarium)

• western poison oak (Toxicodendron diversilobum)

• poison sumac (Toxicodendron vernix)

Regardless of the species name all the treatment protocols are the same. Allergic Contact Dermatitis (ACD) has 2 distinct phases.

• A sensitization phase where a specific hypersensitivity to the allergen is acquired.

• An elicitation phase during which dermatological response is visible. The symptoms may occur within 12-48 hours.

Identification of Poison Ivy:

· Poison ivy is typically a hairy, ropelike vine with three shiny green (or red in the fall) leaves budding from one small stem. “Leaves of three let them be!” and “Hairy vine, no friend of mine”.

· May have yellow or green flowers and white to green-yellow or amber berries

· Poison sumac, may be harder to identify because it more often forms leaflets of five, seven, or more that angle upward toward the top of the stem. Poison sumac presents as a woody shrub that has stems that contain 7-13 leaves arranged in pairs