Understanding Head Lice Infestation

Humberto J. Rivas, MD
Docs 4 Kids, PA

PEDIATRICIAN

1110 N. Sarah DeWitt Dr.

Gonzales, TX 78629

(830) 672-8473

Understanding Head Lice Infestation

Epidemiology & Risk Factors

In the United States, infestation with head lice (Pediculus humanus capitis) is most common among preschool- and elementary school-age children and their household members and caretakers. Head lice are not known to transmit disease; however, a secondary bacterial infection of the skin resulting from scratching can occur with any lice infestation.

Getting head lice is not related to the cleanliness of the person or his or her environment. Head lice are mainly spread by direct contact with the hair of an infested person. The most common way to get head lice is by head-to-head contact with a person who already has head lice. Such contact can be common among children during play at:

• School
• Home
• Elsewhere (e.g., sports activities, playgrounds, camp, and slumber parties)

Uncommonly, the transmission may occur by:

• Wearing clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons worn by an infested person
• Using infested combs, brushes, or towels
• Lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with an infested person

Reliable data on how many people get head lice each year in the United States are not available; however, an estimated 6 million to 12 million infestations occur each year in the United States among children 3 to 11 years of age. Some studies suggest that girls get head lice more often than boys, probably due to more frequent head-to-head contact.

In the United States, infestation with head lice is much less common among African-Americans than among persons of other races. The head louse found most frequently in the United States may have claws that are better adapted for grasping the shape and width of some types of hair but not others.

Disease

Head lice are not known to transmit any disease and therefore are not considered a health hazard.

Head lice infestations can be asymptomatic, particularly with a first infestation or when an infestation is light. Itching ("pruritus") is the most common symptom of head lice infestation and is caused by an allergic reaction to louse bites. It may take 4-6 weeks for itching to appear the first time a person has head lice.

Other symptoms may include:

• A tickling feeling or a sensation of something moving in the hair
• Irritability and sleeplessness
• Sores on the head caused by scratching

These sores caused by scratching can sometimes become infected with bacteria normally found on a person’s skin.

Treatment

General Guidelines

Treatment for head lice is recommended for persons diagnosed with an active infestation. All household members and other close contacts should be checked; those persons with evidence of an active infestation should be treated. Some experts believe prophylactic treatment is prudent for persons who share the same bed with actively-infested individuals. All infested persons (household members and close contacts) and their bedmates should be treated at the same time.

Retreatment of head lice usually is recommended because no approved pediculicide is completely ovicidal. To be most effective, retreatment should occur after all eggs have hatched but before new eggs are produced. The retreatment schedule can vary depending on whether the pediculicide used is ovicidal (whether it can kill lice eggs).

When treating head lice, supplemental measures can be combined with recommended medicine (pharmacologic treatment); however, such additional (non-pharmacologic) measures generally are not required to eliminate a head lice infestation. For example, hats, scarves, pillowcases, bedding, clothing, and towels worn or used by the infested person in the 2-day period just before treatment is started can be machine washed and dried using the hot water and hot air cycles because lice and eggs are killed by exposure for 5 minutes to temperatures greater than 53.5°C (128.3°F). Items that cannot be laundered may be dry-cleaned or sealed in a plastic bag for two weeks. Items such as hats, grooming aids, and towels that come in contact with the hair of an infested person should not be shared. Vacuuming furniture and floors can remove an infested person's hairs that might have viable nits attached.

Treat the infested person(s): Requires using an over-the-counter (OTC) or prescription medication. Follow these treatment steps:

1. Before applying treatment, it may be helpful to remove clothing that can become wet or stained during treatment.
2. Apply lice medicine, also called pediculicide, according to the instructions contained in the box or printed on the label. If the infested person has very long hair (longer than shoulder length), it may be necessary to use a second bottle. Pay special attention to instructions on the label or in the box regarding how long the medication should be left on the hair and how it should be washed out.
3. Have the infested person put on clean clothing after treatment.
4. If a few live lice are still found 8-12 hours after treatment but are moving more slowly than before, do not retreat. The medicine may take longer to kill all the lice. Comb dead and any remaining live lice out of the hair using a fine-toothed nit comb.
5. If, after 8-12 hours of treatment, no dead lice are found and lice seem as active as before, the medicine may not be working. Do not retreat until speaking with your health care provider; a different lice medicine (pediculicide) may be necessary. If your health care provider recommends a different pediculicide, carefully follow the treatment instructions contained in the box or printed on the label.
6. Nit (head lice egg) combs, often found in lice medicine packages, should be used to comb nits and lice from the hair shaft. Many flea combs made for cats and dogs are also effective.
7. After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2-3 days may decrease the chance of self-reinfestation. Continue to check for 2-3 weeks to be sure all lice and nits are gone.
8. Retreatment generally is recommended for most prescription and nonprescription (over-the-counter) drugs on day 9 in order to kill any surviving hatched lice before they produce new eggs. However, if using the prescription drug Malathion, which is ovicidal, retreatment is recommended after 7-9 days ONLY if crawling bugs are found.

WARNING: Do not use a combination shampoo/conditioner or conditioner before using lice medicine. Do not re-wash the hair for 1-2 days after the lice medicine is removed.

Supplemental Measures: Head lice do not survive long if they fall off a person and cannot feed. You don't need to spend a lot of time or money on housecleaning activities. Follow these steps to help avoid re-infestation by lice that have recently fallen off the hair or crawled onto clothing or furniture.

1. Machine wash and dry clothing, bed linens, and other items that the infested person wore or used during the 2 days before treatment using the hot water (130°F) laundry cycle and the high heat drying cycle. Clothing and items that are not washable can be dry-cleaned

OR

Sealed in a plastic bag and stored for 2 weeks.

1. Soak combs and brushes in hot water (at least 130°F) for 5-10 minutes.
2. Vacuum the floor and furniture, particularly where the infested person sat or lay. However, the risk of getting infested by a louse that has fallen onto a rug or carpet or furniture is very small. Head lice survive less than 1-2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the human scalp. Spending much time and money on housecleaning activities is not necessary to avoid reinfestation by lice or nits that may have fallen off the head or crawled onto furniture or clothing.
3. Do not use fumigant sprays; they can be toxic if inhaled or absorbed through the skin.

Prevention & Control

Head lice are spread most commonly by direct head-to-head (hair-to-hair) contact. However, much less frequently they are spread by sharing clothing or belongings onto which lice have crawled or nits attached to shed hairs may have fallen. The risk of getting infested by a louse that has fallen onto a carpet or furniture is very small. Head lice survive less than 1-2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the scalp.

The following are steps that can be taken to help prevent and control the spread of head lice:

• Avoid head-to-head (hair-to-hair) contact during play and other activities at home, school, and elsewhere (sports activities, playground, slumber parties, camp).
• Do not share clothing such as hats, scarves, coats, sports uniforms, hair ribbons, or barrettes.
• Do not share combs, brushes, or towels. Disinfect combs and brushes used by an infested person by soaking them in hot water (at least 130°F) for 5-10 minutes.
• Do not lie on beds, couches, pillows, carpets, or stuffed animals that have recently been in contact with an infested person.
• Machine wash and dry clothing, bed linens, and other items that an infested person wore or used during the 2 days before treatment using the hot water (130°F) laundry cycle and the high heat drying cycle. Clothing and items that are not washable can be dry-cleaned OR sealed in a plastic bag and stored for 2 weeks.
• Vacuum the floor and furniture, particularly where the infested person sat or lay. However, spending much time and money on housecleaning activities is not necessary to avoid reinfestation by lice or nits that may have fallen off the head or crawled onto furniture or clothing.
• Do not use fumigant sprays or fogs; they are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin.

To help control a head lice outbreak in a community, school, or camp, children can be taught to avoid activities that may spread head lice.

Head Lice Prevention through Essential Oils

When the kids are back to school, so are head lice…this is still a condition dreaded by many parents, as it is a source of anxiety, shame, and stress. Head lice prevention is essential because if you can avoid your kids catching these parasites, this will be better for everyone in the family.

We often only talk about head lice treatment, but preventing head lice infestations is possible, at least to some extent. One of the possible solutions for this purpose is through the use of essential oils. But there are some do’s and don’ts.

Why Do Many Essential Oils Work for Protection?

Head lice are attracted to us because of our distinctive human smell. Essential oils are very fragrant and their strong flavors hide our human smell and keep lice away. Essential oils may act as insect repellents, and this is why they can help prevent head lice.

Warning: Of course, with many other head lice prevention solutions and head lice treatments, there is no scientific evidence that essential oils prevent lice. Research on tea tree oil is quite recent and though several studies have shown the effectiveness of tea tree oil or other essential oils for lice removal, more research is needed and you should be careful when using such oils.

Which Essential Oils Prevent Head Lice?

• Tea tree oil for prevention of head lice: this oil, also known as melaleuca oil, has antiseptic properties and has been traditionally used in many countries as a repellent against head lice. Just put 3 to 5 drops of essential oil on a nit comb and comb the hair, or put a few drops behind the ears or in the neck area. However, tea tree oil does have side effects and should not be used in its pure form on babies, young children, and pregnant women, and should not be applied on a daily basis.

You can also use a commercial tea tree shampoo, but make sure it contains about 5 drops of pure essential oil per ounce of shampoo, or you can make it yourself with the shampoo your child uses, adding 5 drops for every ounce of shampoo.  The same precaution measures apply.

Some people find the oil irritating when used pure so this is a good idea to dilute it with a carrier oil such as olive oil, almond, sesame, or coconut oil. You can still use it straight on insect bites but make sure you make a test on your skin first.

• Eucalyptus essential oil: the main component of this oil is eucalyptol, a key ingredient in many antiseptic mouthwashes. Studies have shown that eucalyptus has effects on insects. It works as an insect repellent on head lice. However and unlike tea tree essential oil, it is recommended not to use it with children younger than 5.

You can also use the following oil for head lice prevention: lavender essential oil also has a strong flavor that will repel lice. Rosemary essential oil also has antiseptic properties. Peppermint oil has a strong flavor that would hide the human smell and keep lice away. You should avoid contact with your eyes and sensitive skin areas.

Are Essential Oils Safe to Use for Head Lice?

Many essential oils are very powerful and although natural they can be harmful to us. Most of them should not be applied pure (straight or undiluted) but should be diluted instead. You can dilute pure essential oils with a carrier oil, such as olive, coconut, almond, sesame oils. The best thing to do is read the directions of each oil carefully and always apply and use with great care.

References 

Akram Astani, Jürgen Reichling, Paul Schnitzler -Comparative study on the antiviral activity of selected monoterpenes derived from essential oils – http://onlinelibrary.wiley.com/doi/10.1002/ptr.2955/abstract

J. HEUKELBACH, D. V. CANYON, F. A. OLIVEIRA, R. MULLER, R. SP – In vitro efficacy of over-the-counter botanical pediculicides against the head louse Pediculus humanus var capitis based on a stringent standard for mortality assessment – http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2915.2008.00738.x/abstract

Clive Mills, Brian V. Cleary – Inhibition of acetylcholinesterase by Tea Tree oil – http://onlinelibrary.wiley.com/doi/10.1211/0022357022773/abstract
Webmd.com – Tea tree oil

CDC.org web site