It is this poisonous oil which causes the skin irritation identified with poison ivy. Although contact with the plant is normally the method of poisoning, an individual can also be poisoned by handling clothing, tools, objects or animals which have become contaminated with the oil. The symptoms associated with poisoning usually appear within 12 to 24 hours but may appear in as little to 3 or 4 hours or be delayed for several days. The time span is dependent upon an individuals sensitivity, the amount of oil that contacted the skin, and the season. Spring and summer are the times of greatest potential for poisoning.
Damaged leaves exude the oil, which is easily transferred to skin, clothes and objects.
Symptoms are itchiness, skin inflammation, swelling and the formation of blisters. Two general methods available for control of poison ivy are cultural and chemical. Cultural methods should not be attempted unless the individual is extremely tolerant to poison ivy. Individual sensitivity to poison ivy varies greatly. Natural immunity is originally present in all persons, but is reduced through time by contact with the poison.