How do Poison Ivy, Oak, and Sumac cause the symptoms associated with it?
The itching, redness, and swelling associated with contact with poison ivy is due to the body’s response to the oil, urushiol. This oil is by itself somewhat harmless, but the human body responds in such a way as to attack the dermal layer in which the urushiol is bound. This attack upon the dermal layers is what causes the itching, swelling, and redness.
