A poison ivy rash is one type of skin rash that can occur when contact is made with the poison ivy plant. Poison oak and poison sumac are two other commonly found outdoor plants that also cause an adverse skin reaction.
The skin rash is caused by a sap known as urushiol that is excreted from the plant. The sap causes an allergic skin reaction in many people, although not everyone reacts to the sap. Estimates are that up to 30% of people do not react to the sap from these poisonous plants.
The symptoms listed below usually begin to appear on the skin about 8 to 48 hours after contact with the sap from the poison ivy, poison oak, or poison sumac. The rash appears where direct contact with the sap occurred and therefore if the sap spreads around on the skin, then the poison ivy rash will spread to those locations as well. Actually, contact with the plant itself is not always necessary for the skin rash to appear. For example, if contact of the skin occurs with clothing, garden tools, or pets that have the sap on them, then the poison ivy skin rash can still occur.
The poison ivy skin rash usually takes about 10 days to clear, but can in some cases take up to three weeks. For individuals that have come in contact with a lot of sap, the poison ivy rash can be severe. The same is true for those that are severely allergic to the sap. Very large and widespread blisters may form. Also, the victim can experience swelling of the face, mouth, eyelids, etc. Medical attention should be pursued immediately when these allergic signs are present, especially if the victim is having trouble breathing.