Everything to Know About Head Lice

Head lice are small, wingless insects that live on the human scalp and feed on the blood of their hosts (ugh!). A single bug is called a louse, while the term for multiple bugs is lice.

Contrary to popular belief, lice aren’t a result of poor hygiene. In fact, head lice actually prefer clean hair as it is easier for them to attach and lay their eggs. They also don’t jump or fly—they must crawl in order to spread.

“Head lice are spread mostly from person to person through direct head-to-head [or] hair-to-hair contact, or occasionally from sharing of [objects],” says Dr. Albert Yan, a professor of paediatrics and dermatology and co-author of the new AAP policy. Yan says that this can happen, for instance, when kids are napping or playing together.

Because lice don’t jump or fly, it’s not necessary to isolate kids at home. While “no-nit” policies are still common in many Canadian school boards, the Canadian Paediatric Society (CPS) updated its guidelines in 2008 to say that such policies are no longer recommended.

“Kids can attend school so long as appropriate precautions are taken to avoid head-to-head contact,” says Yan.

The CPS does recommend that families of children in the same classroom or childcare group where a case of active head lice has been detected should be alerted.

What lice look like will depend on where they are in their lifecycle. Adult lice are about the size of a small ant with pointed bodies. Head lice come in a range of colours from tan to grayish-white, and appear different shades on different types of hair. The same thing goes for nits, which stick to individual hair and are slightly smaller than a sesame seed. 

"Keep an eye out for lice and their eggs, or nits, and an itchy scalp," advises Dr. John Barbara IV, DO, a pediatric expert at Children’s Hospital New Orleans. He mentions these are the tell-tale signs of lice. Interestingly, not everyone feels itchy, so don't wait for the itch to start doing head checks.

Why the itch, though? Dr. Barbara explains to Today’s Parent that it's all about how our skin reacts to lice saliva. It might even take a month or more for your skin to start itching after the lice have made themselves at home.

Apart from nits and lice, Dr. Barbara also points out that other signs of lice could include skin irritations on the scalp, particularly at the back of the neck and behind the ears.

If you suspect your child has lice (or you got that notice), you should inspect their hair. You might see the bugs moving about while brushing, but they can also be hard to spot. You’re more likely to spot nits along the hair shaft, particularly around the ears and nape of the neck. Part your child’s hair in sections, and move from one side to the other, and from front to back.

Those of us of a certain age might remember the occasional lice check happening at school, but the AAP states that head lice screening programs in schools have not been proven to have a significant effect on the incidence of head lice in the school setting, are not cost-effective, and may stigmatize children suspected of having head lice. Instead, the group suggests that schools offer educational programs for families to help increase understanding and management of head lice in the community.

Dr. Arianna Rodriguez, ND, who is a naturopathic physician and also an assistant professor at the College of Naturopathic Medicine, mentions that since lice spread through direct contact, there’s no need to search and treat your entire home for lice.

However, she did tell Today's Parent that you should definitely wash any hairbrushes, clothes, or bedding the person with lice used recently. “That will  help keep the lice from spreading further,” Dr. Rodriguez explains to Today’s Parent.

Both lice and dandruff can underlie an itchy scalp, so it’s important to know the difference before initiating treatment. Whereas lice lay eggs on the hair shaft, dandruff is mostly visible on the scalp before flaking and falling off. Lice and nits are more oblong and pointed than dandruff flakes which look like, well, flakes.

Hair casts, which are elongated cylindrical pieces of dandruff that encase a hair shaft, could easily be mistaken for nits, but nits are oval-shaped and much harder to remove.

Dr. Barbara says dealing with head lice doesn't always mean a trip to the clinic. You can actually manage it at home. However, he does recommend touching base with your doctor first because there's a variety of medicines to consider.

Dr. further elaborates, “Some head lice medicine called topical pediculicides (permethrin, pyrethrins, ivermectin, spinosad, etc.) and manual removal of lice using ‘wet combing,’ are the treatments for lice. There are also topical pediculicides, which are applied to dried hair, and should be rinsed off with warm water after ten minutes in the sink.”

Taking care of your hair after treatment is key. According to Dr. Barbara,

“Hair should not be washed with shampoo for 24 to 48 hours after treatment.”

It's also crucial to keep up with any medications you're using. Some might even need a second round of treatment about a week to ten days later.

The CPS recommends products containing pyrethrins and permethrin, chemicals known as pediculicides, which are pesticides designed specifically for killing lice. These products are available most commonly as lice shampoo, which is applied to the scalp and hair, left to sit, and then rinsed out. The AAP, however, recently updated its guidelines due to the increasing resistance of lice in certain areas of the country to these products, as well as the addition of new products to the market. 

“I have a low threshold for moving patients to some of the newer treatments, which have a good safety track record,” says Yan. Unfortunately, most of the newer treatments highlighted in the updated AAP guidelines aren’t available in Canada, like topical ivermectin, topical spinosad, and over-the-counter products containing dimethicone.

There are some treatments that are available in Canada but not the U.S., including isopropyl myristate 50%, sold under the brand name Resultz, a hair rinse that kills lice by dissolving the waxy exoskeleton of lice. It is suitable for children over the age of four. Canadians can also access a non-insecticidal product containing silicone oil dimethicone (Nyda), which is OK for children over the age of two. 

Whatever treatment you decide on, Yan notes that carefully communicated instructions on the proper use of products are important. He also noted that since many products don’t kill lice eggs, a second application at the proper interval according to the manufacturer’s guidelines may be needed, and manual removal of eggs after treatment could be useful—and ease the social stigma of being the kid with lice.

Another treatment method recommended by the AAP, especially if the child is too young for the above treatments or if parents do not wish to use a pediculicide (which, it should be noted, are believed to have a very low toxicity for humans), is wet combing. This involves the removal of lice by combing wet hair with a fine-toothed lice comb for at least three weekly cycles to match the 21-day lifecycle of a louse. (For its part, the CPS does not recommend wet combing as an effective treatment when compared to insecticidal options.)

There are a lot of home remedies for lice that many a desperate parent has tried in order to get some relief, but while some may be effective, some can be downright dangerous.

“There are a number of herbal remedies that include essential oils that have been touted as effective head lice treatments. Unfortunately, there is not much scientific data yet supporting their use, and there is a risk that some of these may pose a risk for [irritation],” says Yan. “In addition, some essential oils [like] have been found to have some properties that may cause hormonal disturbances.”

In the U.S., the AAP discourages the use of products without FDA approval for lice treatment due to lack of evidence of efficacy. The CPS goes further, saying: “Using flammable, toxic and dangerous substances like gasoline or kerosene to treat head lice or using products intended for treating lice in animals are not recommended under any circumstances.”

What about occlusive substances like mayonnaise, petroleum jelly, or mineral oil? While the CPA acknowledges that applying a thick coating of such agents to the hair and scalp and leaving it on overnight would theoretically suffocate the bugs, topical insecticides are far more effective.

Another popular at-home treatment is to use a blow dryer to heat and dry out the lice and nits in order to kill them. While there is an FDA-approved device for just this purpose (known as the AirAllé or Lousebuster), it is expensive and requires special training to use properly. A regular blow dryer is not recommended as investigators have shown that wind and blow dryers can cause live lice to become airborne (eek!) and potentially spread to others nearby, like, for example, you. 

Yan says that since not all communities will have the same level of resistance to the permethrin or pyrethrins in some OTC products, it’s reasonable to try these first. 

“If they don’t seem to be working, it is probably time to consider using the dimethicone-based treatments,” he says, “or to check in with your paediatrician or dermatologist to consider other prescription products.”

While you're unlikely to prevent head lice entirely, you can lessen your child’s chances of catching it by encouraging them not to share things that come in contact with the head, such as combs, hats, hair accessories, and pillows. Regular checks are the best way to detect and treat an infestation early before it spreads to others.

We also love these lice prevention shampoos.

Best lice treatment products

Nit Free Terminator Lice Comb

This specialized comb features micro-grooved teeth that effectively target, lift and remove lice and nits. The teeth have softly rounded ends that make the experience painless. It's made of stainless steel that's durable, rust-resistant and easy to sanitize for repeated use. Be sure to comb as close to the scalp as possible, since lice like to stick close to the skin. Section off small segments of wet hair and work the comb in multiple directions, all the way down to the ends. Keep running the comb through hair until it comes out free of lice or nits.

Lice Shield Shampoo & Conditioner

This 2-in-1 formula gently cleanses and conditions hair while repelling lice. It's packed with essential oils that keep lice at bay, including citronella, rosemary, lemongrass, cedar and geraniol. Note that this shampoo and conditioner is a deterrent and does not treat existing lice. It's ideal as a preventative measure for crowded schools and daycares that are prone to lice infestations.

Fairy Tales Lice Good-Bye No-Drip Mousse

This lice treatment is clinically proven to remove lice and dissolve residue on the scalp leftover by nits. It's a safe, naturally-derived formula containing yeast and alcohol — since lice are increasingly becoming resistant to pesticides, this non-toxic formula may be more effective at treating certain infestations. Cover the entire scalp with the mousse and work it into wet hair, through to the ends. Do not wash out the mousse and follow with combing the dead lice and nits from the hair. Those with a gluten allergy should not use this product.

Malathion 0.5 % Lotion

This malathion 0.5% lotion is designed for direct application on the scalp and dry hair. It effectively treats both lice and eggs. For best results, do not shampoo or condition hair prior to use. According to the Mayo Clinic, this treatment should remain on the hair and scalp for 8-12 hours, followed by a non-medicated shampoo. After rinsing the hair, use a dedicated comb to remove lice and nits. If lice are still present after 7-9 days, repeat with a second application. This lice medication requires a prescription from your child's doctor.

LADIBUGS One and Done Lice Treatment Kit

This all-in-one lice treatment kit contains 100% natural ingredients and offers a three-step solution. First, apply the lice-killing mint serum to dry hair. Let the serum sit for 15 minutes before washing it out. Next, apply the mousse to damp hair to eliminate the nits and prevent future infestations. Leave the mousse in for 5 minutes, reapply it and wait another 5 minutes. Use the specialized comb to lift dead lice and nits from the hair (do not wash out the mousse).