Lice are highly dependent on human blood to survive, and they cannot live long when separated from a host. On average, a louse can only survive for about 1-2 days stages of lice off the human scalp. This limited survival period is because lice lack the ability to store nutrients and must feed regularly to stay hydrated and nourished. Without access to blood, they quickly dehydrate and die.

Temperature also plays a role in how long a louse can survive away from the scalp. Human body temperature provides the warmth that lice need, and a cooler environment (such as bedding, furniture, or clothing) accelerates their dehydration. While lice can cling to fabrics and other materials temporarily, they are unlikely to survive long enough to spread to a new host in these environments.

However, even though lice do not live long off the scalp, it’s still important to clean or disinfect items like pillowcases, hats, and hair accessories that may have come into contact with an infested person. This helps reduce the chance of lice spreading from these surfaces to others in close proximity.