How long does poison ivy last? Poison ivy symptoms typically last 1 to 3 weeks without treatment. However, severe cases can linger for up to 6 weeks. The duration varies based on individual sensitivity, the amount of exposure, and the effectiveness of treatment. To alleviate symptoms and speed up recovery, it's crucial to avoid scratching, apply cool compresses, use calamine lotion or hydrocortisone cream, and seek medical attention if symptoms are severe.