Poison Ivy or Poison Oak is the most common cause of allergic skin reactions. Around 50% of the adult population is clinically sensitive to these plants.
The oil or resin on the leaves, stem and root of this plant is the culprit. The allergic principle is Uroshiol. It is colorless, or may have a slight yellow tinge. In a fire, Uroshiol is carried in smoke and can be carried downwind. The oil can also be on the coats of animals and can be transmitted to humans this way also.
The amount of Uroshiol in the plant is equally present year round.
The weeds do not grow in Alaska or Hawaii, and cannot survive above 4,000 feet. Generally, Poison Ivy grows east of the Rockies and Poison Oak west of the Rockies, and Poison Sumac is usually found in the southeastern United States. Once the oil is on the skin, a person has around 1-4 hours to wash it off. This rash usually starts within 2-6 hours after exposure, depending on sensitivity.
Auerbach, Paul S., Wilderness Medicine,Mosby, 2001: Pages 1092-1100.
The oil or resin on the leaves, stem and root of this plant is the culprit. The allergic principle is Uroshiol. It is colorless, or may have a slight yellow tinge. In a fire, Uroshiol is carried in smoke and can be carried downwind. The oil can also be on the coats of animals and can be transmitted to humans this way also.
The amount of Uroshiol in the plant is equally present year round.
The weeds do not grow in Alaska or Hawaii, and cannot survive above 4,000 feet. Generally, Poison Ivy grows east of the Rockies and Poison Oak west of the Rockies, and Poison Sumac is usually found in the southeastern United States. Once the oil is on the skin, a person has around 1-4 hours to wash it off. This rash usually starts within 2-6 hours after exposure, depending on sensitivity.
Auerbach, Paul S., Wilderness Medicine,Mosby, 2001: Pages 1092-1100.
