Poison ivy itself is not contagious, meaning the rash cannot be spread from person to person by touching the rash or the blisters. The rash only occurs where the skin has come into direct contact with the plant's oil, urushiol

. The urushiol oil that causes the rash can remain on skin, clothing, tools, pets, and other surfaces for a long time-sometimes years-until it is thoroughly washed off with soap and water or rubbing alcohol

. If the oil remains on these surfaces, it can cause new rashes upon contact. The rash itself typically lasts about 1 to 3 weeks, with the worst symptoms often appearing 4 to 7 days after exposure. The rash does not spread by scratching or touching the blisters because the fluid inside them does not contain urushiol oil

. In summary:

• Poison ivy rash is not contagious person-to-person.
• The rash lasts about 1 to 3 weeks.
• Urushiol oil can remain contagious on surfaces for years if not cleaned.
• The rash only develops where urushiol oil contacts the skin.
• The rash cannot spread across the body unless urushiol oil is still present on the skin.

Proper washing of skin, clothing, tools, and pets after exposure is essential to prevent new rashes