How does poison ivy affect human body systems?

Poison ivy affects the human body primarily through skin contact, causing an allergic reaction due to the oil urushiol found in the plant. This reaction typically manifests as an itchy, red rash and blisters, resulting from the immune system's response to the allergen. In some cases, exposure can lead to more severe symptoms, including swelling and discomfort in the affected areas. If inhaled, urushiol can also irritate the respiratory system, leading to coughing and difficulty breathing.