Lice are wingless parasitic insects that feed on blood and infest the hairy parts of human bodies. Humans are affected by three types of lice; head, pubic and body lice. Body lice are the result of extreme overcrowding and poor sanitation.

While head and pubic lice attach their eggs to the base of the hair shaft, body lice attach their eggs onto clothing. Eggs hatch in 6 – 9 days and require warm temperatures to survive, but can survive 2 – 10 days away from the host, depending on the type of louse.

Lice can live from 20 – 30 days and will produce 5 eggs per day during this time. As their name implies, head lice can be found in the scalp area, and pubic lice are generally found in the pubic area, but can also be found in eyebrows and armpits.

Lice are from 1.5 to 3mm (1/16 to 1/8 inch) or about the size of a sesame seed, in length with a flat elongated body and are spread through personal contact and the sharing of such items as combs, brushes, clothing and bedding. Pubic lice tend to spread by sexual contact.

Head Lice

Head lice occur in all socioeconomic groups and are not a sign of uncleanness. Anyone can get head lice under the right conditions, but are most commonly found in elementary school and day care children. Lice can spread as long as they are alive on hair or clothing. Itching is the most common symptom of a head lice infestation, but children with a light infestation may not show any symptoms. This makes a thorough examination of the hair and scalp necessary. Itching may occur two or three weeks after infestation with head lice.

Medicated shampoos, cream rinses and soaps are used to kill lice. They are available from you doctor, or over the counter. Follow the directions on the label and repeat the process in 7 – 10 days to kill any lice which hatched after the first treatment.

To prevent becoming infected:

  • Don’t share combs, brushes, hats, or other headgear. These and similar items should be soaked for 10 minutes in a pan of hot water (128 degrees F – 58 degrees C), or by soaking them in a medicated shampoos for 1 hour.
  • Clothing, sheets, blankets and bedspreads should be washed in hot water for five minutes to destroy eggs and lice. Storing clothing in plastic bags for ten days is also effective.
  • Vacuum the furniture and carpets.


Signs, symptoms & indicators of Lice

Symptoms - Reproductive - General  

Genital itching

Counter Indicators
Symptoms - Reproductive - General  

Absence of genital itching

Risk factors for Lice

Symptoms - Reproductive - General  

History of genital itching

Recommendations for Lice

Physical Medicine  

Hot Applications

Pediatrics, November 6, 2006 – University of Utah biologists invented a chemical-free, hairdryer-like device – the LouseBuster – and conducted a study showing it eradicates head lice infestations on children by exterminating the eggs or “nits” and killing enough lice to prevent them from reproducing.

The study “shows our invention has considerable promise for curing head lice,” says Dale Clayton, a University of Utah biology professor who led the research and co-invented the machine.

“It is particularly effective because it kills louse eggs, which chemical treatments have never done very well,” he says. “It also kills hatched lice well enough to eliminate entire infestations. It works in one 30-minute treatment. The chemical treatments require multiple applications one to two weeks apart.”

The LouseBuster now is in early stages of commercial development by a University of Utah spinoff company, Larada Sciences, for which Clayton is chief scientific officer. Patents are pending on the LouseBuster technology, which Clayton hopes will be on the market within two years for use in schools and clinics.

“Each year, millions of children are infested with head lice, a condition known as pediculosis, which is responsible for tens of millions of lost school days,” the study’s authors write. “Head lice have evolved resistance to many of the currently used pediculicides [insecticide shampoos]. Hot air is an effective, safe treatment and one to which lice are unlikely to evolve resistance.”


Weak or unproven link
Strong or generally accepted link
Strongly counter-indicative
Likely to help



(mm): A metric unit of length equaling one thousandth of a meter, or one tenth of a centimeter. There are 25.4 millimeters in one inch.


A drug or medication that can legally be bought without a doctor's prescription being required.

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