Myths and Facts

Head Lice Common Myths and Facts


Myth: Head lice carry disease

Fact: Lice neither carry nor transmit disease. Lice are a nuisance to humans, not a health hazard. Lice infestations are not a medical condition or disease but have become a social disease.

Myth: Lice jump or fly from one head to another.

Fact: Lice have 6 legs with claws for grasping hair. They do not have wings so cannot fly. The claws prevent jumping. Lice crawl, grasp hair and swing from hair to hair like a trapeze artist.

Myth: Lice are easily transmitted in the school setting.

Fact: Close hair-to-hair contact is necessary to transfer lice to a new head. Bed sharing is the most common situation for the transference of lice. In order for an infestation to occur a male and a female louse or an inseminated female must be acquired. Scientific sources agree that the school is not a significant source of head lice infestation.

Myth: An unclean house, dirty or long hair, and low socioeconomic status contribute to lice infestations.

Fact: Lice have no preference for any particular group, dirty or clean, long or short hair. As long as there is a warm, moist scalp, and a blood supply as a food source, it’s a good home for lice. That means everyone’s scalp is a potential home for lice.

Myth: Lice can be transferred by inanimate objects such as hats, combs, coats hanging in the same place, furniture, headphones, or helmets.

Fact: The life cycle of a louse must be completed on a head. Lice die very quickly off the head. Lice must suck blood every six hours or they will dehydrate and die. Eggs (nits) need the warmth and moisture of the scalp. Lice need the warmth, moisture and food source of the scalp to live and breed. Healthy lice do not leave healthy heads. Lice are unable to grasp anything but human hair. They cannot grasp objects such as helmets or headphones. The fibers of hats, coats or furniture and the teeth of a brush or comb are too large for the lice to grasp.

Researchers have tried to transfer lice by using inanimate objects but have not had success. Hats worn by 1000 students were examined and no head lice were found on the hats even though many lice were found on the children’s heads.

Myth: Lice can be picked up off of carpets.

Fact: Lice that fall off the scalp are usually damaged and not viable. Lice cannot grasp the carpet fibers and die without a blood source. In one study 118 carpeted classrooms were examined. No live lice or eggs were found, even though 14,563 lice were found on the heads of students in these classrooms.

Myth: Itching is often a sign of lice.

Fact: Itching due to lice is a result of the saliva that mixes with the blood as the lice feed on the scalp. This saliva is what causes the itching sensation but may not develop for 4-6 weeks when the host develops sensitivity to the saliva. Itching may also result after treatment with a lice shampoo and is a result of the irritation of the shampoo and not a sign of treatment failure.