Head Lice Are Equal-Opportunity Invaders

Head lice find an easy pathway to spread with kids, because children plan in such close proximity of one another.

head lice

Head lice are diagnosed by sight. Spread the hair apart and look for tiny specks. Most likely you’ll see nits (lice eggs), which are the tiny white-yellow-tan specks attached to the individual hair.

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Lice! The very word sends chills down the spines of any parent. My mother, a registered nurse who worked in elementary schools, suffered from pediculophobia, which is a fear of ice. The words “head lice” caused her scalp to itch, and we children were never allowed to try on hats at stores or share hats with friends for fear of picking up head lice. As it turns out, she may have been overreacting just a tad—although there are way more head-lice treatments now than there were a few decades ago. But head lice are surely not a thing of the past. According to the American Academy of Pediatrics, six to 12 million school-age children get head lice each year.

While head lice are a year-round problem, the number of cases seems to peak when the kids go back to school in the fall and again in January, says Patricia Brown, M.D., a dermatologist at the Food and Drug Administration (FDA).

Head-Lice Transmission

Lice cannot fly or hop. They crawl. So, it takes close contact to transmit head lice from person to person, which is why children are major players in their spread and why head lice can infiltrate an entire family quickly. Kids and families spend a lot of time near one another, making head-to-head lice contact easy.

Mom wasn’t entirely wrong about head lice and hats, however. Although the CDC says methods of transmission other than head-to-head are “uncommon”—possibly because lice only live a day or two without food (human blood) and nits (microscopic lice eggs) cannot hatch if away from the warmth of the human scalp—it is possible to get head lice from hats and more, if the timing is right. Head lice can be transferred via items like shared:

  • Carpeting
  • Clothing
  • Furniture
  • Hair brushes and combs
  • Stuffed animals
  • Towels and blankets

It’s important to understand that lice do not discriminate. They are equal-opportunity pests, regardless of race, income, religion, or housekeeping ability. Anyone can get head lice, no matter how “clean” they are (or aren’t). While three different species of lice can infect people, only the body louse transmits disease (see sidebar).


University of Florida researcher David Reed lead a five-year study on the evolution of lice. The study found that human clothing—which people began wearing about 170,000 years ago—enabled lice to migrate out of Africa.

Symptoms of Head Lice

If you or your child have head lice, the first symptom is usually an itchy scalp, most often behind the ears and/or at hairline at the back of the neck.  The itching is an allergic reaction to head lice saliva, which is transmitted when they bite.

Head lice are diagnosed by sight. Spread the hair apart and look for tiny specks. Most likely you’ll see nits (lice eggs), which are the tiny white-yellow-tan specks attached to the individual hair. Nits look a lot like dandruff, but they’re glued to the hair shaft. Adult head lice are harder to see because not only are they small, but they’re fast and move away from light, explains the American Academy of Pediatrics.

The U.S. National Library of Medicine says additional symptoms of head lice include:

  • Tickling feeling in the hair.
  • Sores from scratching. Sometimes the sores can become infected with bacteria.
  • Trouble sleeping, because head lice are most active in the dark.


Only the body louse is known to spread disease, so antibiotics are not normally needed with head lice, unless a bite or area that has been scratched becomes infected.  Use only FDA-approved lice-removal products (see chart). Research does not support the use of home remedies, such as mayonnaise, olive oil, or similar substances, to “suffocate” head lice. It should go without saying that kerosene and gasoline should never be used, as they are both harmful to the person and flammable.

Pediculosis (the medical term for head lice and body lice) and pthiriasis (pubic lice) can be treated with medications and housecleaning/delousing.  “Many head-lice products are not for use in children under the age of 2, so read the label carefully before using a product to make sure it is safe to use on your child,” Brown says.  To be certain, you should consult your pediatrician or a pharmacist for specific recommendations. These are strong chemicals. If elderly people are involved in the head-lice invasion, consult their primary care physicians before treatment.

Products that kill lice are called pediculicides. If possible, you should choose one that is also ovicidal (meaning it kills eggs, too). If not, you will have to retreat with the pediculicide to kill newly hatched head lice.

Anyone with an active head-lice infestation should be treated, obviously, as well as household members and other close contacts. Many experts advise that if you think someone could be infested, treat them.

Always follow label instructions and never mix products. Apply the product only to the scalp and the hair attached to the scalp. Use exactly as directed. Do not use extra product unless directed by your health-care provider.

After rinsing the product from the hair and scalp use a “nit comb” (available at a pharmacy) to remove dead head lice and nits. (Note: A pet flea comb may work as well.) Use the nit comb every day for two to three weeks to ensure all head lice and nits are removed.

While it’s not always necessary to do housecleaning when you find evidence of head lice, it is often recommended. There is that 24- to 48-hour period where hungry head lice can survive not on a host scalp. That means wash anything washable in hot water. Hot-air drying is also useful to kill head lice.

Lice and eggs can be killed if exposed to temperatures 128.3°F or more for a minimum of five minutes. You can soak things that cannot be put in the washer-dryer in lice-killing product for five minutes. If an item is not washable, it may be sealed in an air-tight plastic bag for two weeks to ensure any head lice are killed.

If active head lice are still present several days after treatment, you will need to re-treat the area. If head lice return after two treatments with a topical product, do not try the product again. Consult your health-care provider, as there may be a resistance problem going on or a treatment error.

FDA-Approved Medications for Lice

Drug Brand Names Prescription Required Comments
Pyrethrins combined with piperonyl butoxide A–200, Pront, R&, Rid, Triple X


No Pyrethrins can only kill live lice, not unhatched eggs (nits). A second treatment is recommended nine to 10 days after the first treatment to kill any newly hatched lice. Not for people allergic to chrysanthemums or ragweed.
Permethrin lotion, 1% Nix No Permethrin lotion 1% is approved by the FDA for the treatment of head lice. Kills live lice and may continue to kill for several days. Second treatment may be needed on Day 9.
Benzyl alcohol lotion, 5% Ulesfia lotion Yes Kills lice but not nits. Second treatment is needed seven days after the first treatment. Can be irritating to skin.
Ivermectin lotion, 0.5% Sklice Yes Not ovicidal but appears to prevent newly hatched lice from surviving. It is effective in most patients when given as a single application on dry hair without nit combing. It should not be used for retreatment without talking to a health-care provider.
Malathion lotion, 0.5% Ovide Yes Malathion is an organophosphate pediculicidal (kills live lice) and partial ovicidal (kills some lice eggs). Second treatment if live lice still are present seven to nine days after first treatment. Can be irritating to the skin. Malathion lotion is flammable.
Spinosad 0.9% topical suspension Natroba Yes Kills live lice and unhatched eggs, so retreatment and nit combing are not usually needed. Repeat treatment should be given only if live lice are seen seven days after the first treatment.


Although different species—humans, dogs, cats, horses, and more—can be tortured by more than one species of lice, a louse is species-specific. In other words, if your child comes home with lice, the dog is safe. Lice are wingless, six-legged whitish/light-brown insects that move by crawling. They survive on the blood of their host, laying eggs in the hair. Without a warm host, lice will die. Their specialized claws allow them to grasp a firm hold of the hair of their host. The nits cannot hatch if they fall from the host, because they require body-temperature warmth to survive. So, unhatched nits in the carpet won’t re-infest your household (you still should vacuum them up, of course!).

Human Lice Species: Pediculus humanus capitis (head louse), Pediculus humanus corporis (body louse, clothes louse), Pthirus pubis (“crab” louse, pubic hair, eyebrows, eyelashes, beards, chest hair, armpits)

Canine Lice Species: Trichodectes canis, Heterodoxus spiniger (rare in North America), Linognathus setosus

Feline Lice Species: Felicola subrostrata

Equine Lice: Haematopinus asini, Bovicola equi, Trichodectes pilosus

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Cindy Foley

Cindy Foley is the editor of several health reports, including Managing Your Cholesterol, Core Fitness, and Brain Power & Nutrition, among others. Foley has worked in the private medical practice field … Read More

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