Head Lice

What is Head Lice?

Both children and adults can become infested by the small insects known as head lice anytime they come in contact with another infested person.

The tiny insects hide in the hair and bite the scalp to drink the blood of its host. Lice can spread through head-to-head contact, sharing a hairbrush, using the pillow of an affected person, and trying on a hat that an infected person recently wore.

What are the Symptoms of Head Lice?

Constant scalp itchiness is the most common symptom caused by head lice. Upon close inspection, you’ll notice sand-like dots on the scalp or at the base of hair strands. These are the eggs, or nits, of the lice.

It’s relatively rare to see adult lice, which are the color and size of a sesame seed, unless the infestation is severe or you’re using a lice comb to pull the insects out of the hair. If you or your child has been scratching with force, you may notice scalp redness or even sores.

Head Lice Causes

Head lice are caused by infestations of a parasitic insect called the Pediculus humanus capitis. The lice feed on human blood by biting at the skin, and they, therefore, tend to live very close to the scalp. It’s possible for them to live in the eyebrows and eyelashes, as well as on the scalp.

Head lice tend to spread from one person to another via close, head to head contact. The lice cannot fly or jump, and only crawl from hair to hair. This means that close contact is necessary for transmission. Although it does occur in rare instances, it is very unlikely for head lice to spread through the shared use of combs or hairbrushes, or items like towels and hats.

Contrary to popular belief, head lice do not occur as a result of poor personal hygiene; the cleanliness of the hair or scalp does not increase or decrease the risk of contracting head lice. Children tend to be most at risk of developing head lice, no doubt because they are more likely to have direct head to head contact with others during play.

How is Head Lice Treated?

Medicated shampoos and hair rinses are the primary treatment most people choose. These treatments are available over-the-counter, but many populations of lice are growing immune to the chemicals and concentrations in these products.

Prescription shampoos approved by your doctor can take care of lice that aren’t responding to the widely available treatments. Alternative options that are reliable include removing the lice by hand every day to break the three day life cycle smothering them by coating the head with vegetable oil for an hour daily. Both of these practices take about two to three weeks of daily use to kill off the entire population, and they’re both good options for children too young or sensitive for chemical-based treatments.

Head Lice Prevention

It may be possible to prevent head lice by avoiding close contact with an infected individual until they have been treated. It can be difficult to ensure infected children avoid close contact with their friends or peers, so in some cases, it can be safer for children with head lice to avoid school, daycare or other environments with lots of other children. In fact, some schools and daycare facilities may have a policy which prevents infected children from attending until they have been treated.

Although it is incredibly rare for head lice to be transmitted by personal care items or clothing, it is good practice to avoid sharing such items with those with head lice. This includes hair brushes and combs, towels, hats, bedding and clothes.

Last Reviewed:
September 14, 2016
Last Updated:
April 08, 2019