How to Get Rid of Lice – An Integrated Pest Management Approach
Head lice infest between 10-12 million Americans each year. Head lice are most common among pre-school and elementary school children between the ages of 3 – 11 years old. If you are battling head lice in your home, it does not mean your home or child is dirty or unsanitary. In young children, head lice are extremely transferable.
Lice are ectoparasitic, meaning they live and feed on the outside of their hosts’ bodies. Lice feed on human blood and remain on the host as they feed every 4 – 6 hours. The good news is, there is no evidence that head lice spread bacteria or disease. However, severe infestations with excessive itching and scratching, may cause secondary infections or anemia. There are 3 kinds of lice that can feed on humans, head lice, body lice, and public lice. This article will focus head lice as they are by far the most common.
Head lice are passed from person to person by close head-to-head contact. Head lice are most common in young children, and more often found on girls rather than boys. While children should be encouraged to not share hats, scarves, hairbrushes, combs, head phones, or other personal belongings new research suggests that fewer lice are transferred in this manner than previously believed. Head lice have specialized feet that have adapted to hold onto human hair. Smooth plastics such as a football helmets and headphones are not easy for head lice to hold onto and travel on.
Lice are more often spread by close head-to-head contact, such as laying on a pillow together while playing on a device or leaning together to whisper secrets and giggle. Head-to-head contact is common in normal child’s play, sports activities, slumber parties, and playground activities. Scroll through the pictures on your phone of your children. They often come together with their heads touching and smile their happiest smiles. That is the sort of contact that is likely to spread head lice.
Head lice do not hop or jump, they can only walk 6 to 30 cm per minute. Although it is uncommon, it is possible to pick up lice from a couch or pillow that was recently used by an infested person. In schools when backpacks, jackets, hats, and scarves are hung on hooks and mingle together, the possibility of spreading lice increases.
To get lice off your children and out of your home, it is helpful to understand the louse life cycle. The head louse has 3 life stages, egg, nymph, and adult. Head lice live their entire life cycle on the human head. Each female louse may lay up to 140 eggs in her lifetime. Lice have a rapid life cycle; an introduction can quickly become a severe infestation. Regular screening for lice and prompt action when lice are identified will make management more effective.
Louse eggs are commonly referred to as nits. A female louse lays a nit at the base of the hair near the scalp. Nits are very small, approximately 0.8 mm by 0.3 mm. Nits are oval shaped and either white or off white in color. The eggs are glued to hairs on the head near the scalp to protect the eggs from extremes in light, humidity, and temperature. The female louse will commonly glue the eggs behind the ears or along the nape of the neck. Unhatched eggs will be within 1 cm of the scalp. In general, nits found more than 1 cm from the scalp are unlikely to survive, but in warmer climates, viable nits can occur farther from the scalp.
Lice nits can be difficult to see and are often mistaken for dandruff flakes or residue from hair products like hairspray or gel. When inspecting for nits, good lighting is essential.
On average, lice eggs hatch within a week to 10 days, and a nymph or immature louse emerges.
Immature lice or nymphs emerge from the egg about a week to 10 days after the female lays the egg. The louse nymph must feed within a few hours or it will die. Louse nymphs can not reproduce, but during this stage, they regularly feed upon their host. As nymphs grow and mature, they molt three times each time appearing more and more like an adult. After about 9-12 days and three molts, the nymph is considered an adult louse and is capable of reproducing.
An adult head louse, Pediculus capitis DeGeer, is approximately 1/8″ in length, about the size of a sesame seed. They are brownish and tan in color and like all insects have 6 legs. Head lice do not have wings, but they do have hook-like claw feet that are specifically adapted to cling to human hair. Adult lice feed upon the scalp every 4-6 hours. The head louse pierces the skin on the scalp of its host with its mouthparts. The louse then sucks blood from the scalp. With no intervention, an adult head louse can live on its host for approximately 30 days. Each female louse can lay up to between 6-8 eggs per day.
However, a louse cannot survive more than 48 hours without a blood meal. If a louse falls off the hair/scalp, it will not survive more than two days without locating another host.
For many, the first sign of lice infestation is a call from the school nurse. Many elementary schools have regular lice inspections and eradication campaigns. Outbreaks are most common in August – November when kids return to school after the summer break. For this reason, September is known as “National Head Lice Prevention Month.”
Other common symptoms of pediculosis include:
- Feeling of tickling or movement on the scalp
- Itching, caused by allergic reactions from the bites
- Secondary infection caused by scratching the sores on the scalp
- Anemia in severe cases
Lice are most active at night. Children with severe infestations, may have difficulty sleeping, and therefore feel tired, irritable, and feverish. In addition to sleep deprivation, infested students may feel embarrassed, and even suffer anxiety. This grouchy and irritable condition of the lice infested has been dubbed, “feeling lousy” or “lousiness.”
Upon getting a call from the school nurse or a note home informing you of lice amongst classmates, closely inspect your child for any signs of lice. Everyone in the family should be inspected. Early detection of lice will prevent advanced infestations, which are much more difficult to control. The presence of active, living lice in a person’s head is the only definitive indication of an infestation that should trigger a head treatment.
Active lice are almost always found on or very near to the scalp. During your inspection pay special attention to the hairline at the back of the head and behind the ears.
- Use a lamp or sit by a window to get good lighting during your inspection.
- Magnification may help, use a hand lens or magnifying glass.
- Shampoo hair.
- If you are going to use a lice treatment product following your inspection and nit removal, do not use a product with conditioners in it. See product label for more specific details.
- Remove tangles with a comb or hairbrush.
- Divide the hair in sections, and fasten the hair that is not being examined.
- A louse or nit comb can be used to examine small sections of hair for head lice.
- Metal lice combs are much better than plastic lice combs in most lice removal kits.
- If lice or nits are discovered, all family members and other contacts (e.g. babysitters, cousins, playmates, teachers, etc.) should be inspected.
- Be careful to not cross contaminate when performing multiple inspections.
Once you have confirmed a lice infestation, you must decide how you want to approach treatment and lice elimination. There are many treatment options, each with distinct advantages and disadvantages. Some people choose to go chemical free and attempt to manually remove lice and nits completely. Others opt to go the drug store route, while others take the recommendation of their doctor.
Although lice are insects, head lice are not necessarily a pest control issue. Despite lice control utilizing some of the same chemicals we use in traditional pest control applications, how you choose to treat an active lice infestation is a medical decision that each family must make for themselves. Spraying pesticides in and around your home to eliminate head lice is unnecessary and ineffective. Since lice live only a short period of time off the host and they are not good at finding the host again if they fall off, treating your home is not necessary. Scalp treatments (medicine or mechanical) for the person affected and laundering all bedding is the best action. If you are concerned about certain items such as some stuffed animals that cannot be laundered, another option is to place these items in a sealed bag for a week. Since lice can only live 1-2 days off the host they will all be dead at the end of the week.
A chemical free lice treatment involves thoroughly and painstakingly inspecting the head and hair of the affected induvial and removing live lice and all the nits. Depending on the length and thickness of the hair, this process can take quite a long time. To ensure the lice from all stages of life have been removed, you should expect to repeat this process daily for 2 weeks.
There are even services available where a Registered Nurse will visit your home and remove nits and lice for you. This is a labor intensive process, but it is possible to be done without using chemical treatments if you are thorough.
Nit or lice egg removal is key to successful manual removal treatments. The female attaches her egg to the hair shaft with a glue-like substance, and her glue is effective. Nits are difficult to remove. Use a metal nit comb, the plastic ones commercially available are ineffective. There are some over the counter products that claim to loosen nits. There is no data available to substantiate these claims.
- Divide hair into manageable sections and clip up the hair that is not being examined.
- Dip comb in hot soapy water between uses to remove lice and eggs.
- Comb the hair to remove lice and eggs one section at a time. Live lice can also be removed with tweezers. Check each section before you move onto the next.
- When finished, clean comb carefully in hot soapy water.
- Vacuum the surrounding area to remove any insects in the carpet
*Products listed are examples and not endorsements.
Many people choose to supplement their manual lice removing efforts with a lice killing shampoo. We recommend speaking to your doctor prior to treating your scalp with any of these products.
Pesticide resistance is well documented in lice. Insecticide resistance is when head lice are exposed to a product but they do not die, similar to antibiotic resistant bacteria that we deal with in humans. The overuse of some common pesticides has rendered them less effective over time. To combat resistance issues, it is imperative that you follow the instructions on any product that you choose to apply and do not continue to use a given product if it is not effective.
Pesticide resistance can be over-come by product rotation. That simply means, choose a product with a different active ingredient than the lice are resistant to. The common over-the-counter products often contain pyrethrum (RID® Lice Killing Shampoo) and permethrin (NIX®). Many lice are now resistant to these active ingredients and they are therefore not effective. By choosing to treat lice with a product that contains a different active ingredient, you may have a better outcome on the first application, thus less exposure to pesticide.
Pediculicide products that contain active ingredients other than pyrethrum and permethrin are only available by a prescription from a doctor. Active ingredients available via prescription include spinosad, ivermectin, and malathion. Spinosad, which is derived from bacteria in soil, kills live lice and unhatched eggs. Studies show that ivermectin and malathion lice products are less effective at killing nits. Talk to your doctor about the benefits and risks of each of these treatments.
With concerns regarding pesticide exposure and the failures of traditional lice treatments, many people turn to natural or homemade lice remedies. There is little scientific data to support its efficacy, but many people claim success at suffocating lice by applying oil-based products. An evening spent with mayonnaise, olive oil, or petroleum jelly in your hair certainly does no harm, but it is unlikely these products will kill the lice eggs. Without effectively removing or killing the nits, the louse life cycle will begin anew.
As you pick insects from your child’s scalp it is perfectly natural to feel the need to clean and sanitize or throw away everything they have recently touched. Remember louse biology though; they can only survive 24-48 hours off their host. They can not jump, hop, or fly, they can only slowly walk. That being said, as a precaution, any items with direct contact such as all clothes, bedding, car seat covers, and other soft furnishings should be laundered or sanitized. There is no need to apply pesticides to these areas.
All clothes, including hats, jackets, and backpacks should be washed in soapy water and dried on a high heat. Pillowcases, sheets, blankets and other bedding material should also be washed and placed in the clothes dryer on the “high heat” cycle for at least 20 minutes to kill the lice and their eggs. Carpets, furniture, car seats and any non-washable items such as children’s toys should be thoroughly vacuumed and the vacuum bag immediately discarded outside of the home. Anything that cannot be vacuumed may be tightly sealed in plastic bags for at least 7 days. Lice will die if they don’t have a blood meal in 48 hours so this ensures they will all be dead.
Spraying pesticides in and around the home for lice is not recommended. It creates unnecessary exposure and will not be effective. As shocking and sickening as it is to think about these insects sucking your child’s blood, spraying pesticide all through the house does not solve the problem. Head lice can not survive off their host for more than 48 hours. Focus your efforts on killing and removing the lice from your family’s heads and laundering or sanitizing direct contact areas.
In recent years, lice removal services have popped up, helping families eliminate lice from their homes. Each of these companies offer slightly different services and the personnel have varying levels of qualifications. Some services will come to your home and comb out your children’s hair and inspect all heads in the family. Others offer a salon type experience where you can take your child for a thorough nit combing session and treatment. Many lice specialty services market their protocol as non-toxic, pesticide free, safe, organic, and 100% guaranteed. We can not speak to the efficacy of these programs, but it is certainly dependent upon the skill and experience of the technician. If all nits and lice are removed your child will be lice-free. Ask careful questions regarding the products they utilize before committing to such a service.