Is the allergin in poison ivy a water soluble or fat-soluble molecule?

The allergen in poison ivy, known as urushiol, is a fat-soluble molecule. This characteristic allows it to easily penetrate the skin's lipid-rich outer layer, leading to an allergic reaction in sensitive individuals. Because it is not water-soluble, urushiol does not wash off easily with water, making it important to use soap or specialized cleansers to remove it from the skin.