Head lice are a creepy crawly nuisance no parent wants to face, but many do. Small and stealthy, these school yard monsters infest anywhere from six to 12 million children every year. Once they’ve found a new home on your child’s head, they can spread to everyone in the household and may be hard to remove.
“Having head lice is fairly common among young children,” says Trieva Scanlan, MD, a pediatrician at Scripps Coastal Medical Center. “Getting it has nothing to do with hair length or hygiene. Anyone who has direct head-to-head exposure can become infested, no matter how often they bathe.”
Head lice are tiny insects that live in human hair and eat blood. These parasites lay eggs—called nits—on strands of hair, close to the scalp. The nits hatch into nymphs before growing into adult lice. A female louse can lay six to eight nits per day, allowing an infestation to happen rapidly.
Contrary to popular belief, head lice cannot jump from person-to-person. They are transmitted from direct head-to-head contact. They can also be transmitted through sharing clothing or articles that have recently been worn or used by an infested child. These include hats, towels, hair ribbons, brushes and pillows.
Unfortunately, other than limiting contact between infected children, there are no known preventive treatments for head lice.
“There are some shampoos and herbs that are said to protect against lice, and there is no harm in trying them,” notes Dr. Scanlan. “However, there is no evidence that they are effective.”
The itching sensation caused by head lice is not caused from bites, but from an allergic reaction that develops to lice saliva. It can take several weeks to feel the itching of an initial infestation, so you may not be aware of a lice problem until it’s infected the entire household. “The best way to protect the rest of the family is with prompt treatment,” notes Dr. Scanlan.
In general, head lice can be treated at home. There are two prominent over-the-counter medications: permethrin and pyrethrin. “These are the least toxic formulas,” says Dr. Scanlan. “They leave a residue on the hair to kill the nits.”
These treatments are washed through the hair. A special nit comb should be used to remove the nits from the hair. Metal nit combs tend to be more effective at removing the sticky eggs. The hair should not be rewashed for one to two days following treatment. For most over-the-counter medications, retreatment is recommended nine days after the initial treatment. Be sure to check product labels for retreatment guidelines. For parents who want help removing the nits, there are specialty hair salons that will apply the treatment and remove the nits.
“We are seeing some resistance to some of the over-the-counter treatments. If they don’t work, it’s time to see a doctor,” adds Dr. Scanlan.
In addition to treating the lice, it’s important to treat the rest of the home to reduce the risk of reinfestation. The Centers for Disease Control and Prevention recommends the following:
- Do not use any fumigator or fogger in the house to treat the lice.
- Machine wash clothing and linens used by an infested person for two days before treatment in water of at least 130 degrees fahrenheit. Items that cannot be washed can put placed in plastic bags for two weeks.
- Vacuum areas where the infested person has been sitting or sleeping up to two days before infestation.
- See a doctor if over-the-counter treatments don’t work or if you need to confirm a diagnosis. Recurrent infestations also warrant a trip to the pediatrician.
Learn more with our head lice infographic. (PDF, 120 KB)