Lice Treatment

There is no treatment or product that can cure a lice infestation 100%. However, there are methods that have been proven successful to varying degrees. Since the mid 1960s, lice outbreaks have increased significantly in the US. Various debates have arisen about the treatment of lice. Generally, each individual should develop their own method for eradicating lice. Various methods include chemical treatments, natural products, combs, shaving, hot air, and silicone-based lotions.

Head Lice Treatments

Head lice are parasitic insects found most commonly behind the ears and near the neckline at the back of the neck. The medical term for head lice infestation is Pediculus humanus capitis. There are 6 – 12 millions cases of head lice in the United States every year more commonly in children than adults. Head lice infestations are actually rare in African Americans possibly because the louse prefers a specific hair shape and width. A head lice infestation can be psychologically disturbing, but head lice are not a health hazard and are not responsible for the spread of any disease.

The life cycle of the head louse has three stages: nit, nymph, and adult. The life cycle of a single louse from egg to egg is about 1 month.

Nits: Head lice eggs are called nits. Nits are laid by the adult female louse and are attached to the base of the hair shaft by strong cement. They are located close to the scalp because they require body heat for incubation.

Nymphs: When an egg hatches, it releases a nymph. The nit shell stays attached to the hair and turns a dull yellow color. The nymph looks like an adult louse but is smaller. As the nymph grows, it molts out of its exoskeleton 3 times before it becomes an adult.

Adult: The adult louse feeds about 5 times a day by piercing the skin with its claws, injecting irritating saliva, and sucking blood. Lice do not become engorged like ticks, but their color changes to a rust color after feeding. Head lice hold onto the hair with hook-like claws found at the end of each of their 6 legs. Adult lice are active and can travel quickly.

Symptoms of Head Lice

Scalp Itching
Sensation of Something Moving in the Hair
Red or Pustular Sores on the Scalp Caused by Scratching
Swollen Lymph Nodes in the Front and Back of the Neck

Transmission of Head Lice

Head lice can be spread by direct contact with the head or hair of an infested person. The adult louse can survive up to 1-2 days without feeding on the scalp; therefore can be found on objects that have been in contact with an infested person. Examples of objects that commonly spread head lice are:

Clothing Such as Hats, Scarves, Coats, and Sports Uniforms
Hair Care Instruments Such as Combs, Brushes, or Towels
Other Objects Such as Pillows, Beds, Carpet, and Stuffed Animals

Diagnosis of Head Lice

A head lice infestation is diagnosed by direct visualization of the lice in any portion of the life cycle. Usually there are many more nits than adults or nymphs. Finding nits within a quarter inch from the scalp confirms an infestation that needs to be treated. Nits can be distinguished from dandruff flakes as they are extremely adherent to the hair shaft, whereas dandruff can be easily moved on along the hair shaft.

Medications that kill head lice are called pediculicides. All pediculicides except malathion are applied to the scalp and hair and left on for 10 minutes, then rinsed off. Pediculicides kill nymphs and adult lice, but do not destroy nits. For this reason, they may need to be reapplied 7-10 days after the first application to kill newly emerged nymphs. Because some pediculicides have significant toxicities, it is important to follow application directions carefully.

Permethrin

Permethrin is the preferred first-line treatment for head lice. Permethrin 1% (Nix) is available over the counter, and permethrin 5% (Elimite) is available by prescription. Permethrin is a cream rinse that is designed to leave a residue after rinsing that kills emerging nymphs, so reapplication is usually not needed.

Pyrethrins Plus Piperonyl Butoxide (Rid)

Rid is a shampoo that can cause an allergic reaction in people who have plant allergies, especially allergies to chrysthanthemums. Twenty to thirty percent of the eggs remain viable after treatment, so a second treatment is recommended in 7-10 days.

Lindane (Kwell)

Lindane is available only by prescription. It should only be used cautiously if a first-line treatment has failed because several cases of seizures in children have been reported.

Malathion

Malathion is a prescription lotion that is applied to the hair, left to air dry, then washed off after 8-12 hours. Because it has a high alcohol content, it is highly flammable and can cause difficulty breathing if it is ingested. For these reasons, it should only be used for resistant cases of head lice.

Oral Agents

Trimethoprim-sulfamethoxazole (Septra, Bactrim) is an oral antibiotic, given as a 10-day course, which has been shown to be effective at treating resistant infestations of head lice. Ivermectin (Stromectol) is an antiparasitic drug given as a single dose that has also been shown to effectively treat resistant head lice infestations. However, neither of these drugs is FDA approved for use as a pediculicide.

Nit Removal

Treatment with a pediculicide kills adult lice and nymphs preventing the spread of head lice infestation to other people. Removal of nits is recommended to reduce confusion about the effectiveness of treatment. Nits within 1 cm of the scalp should be physically removed by a fine toothed comb. A variety of agents are available to break down the cement holding the nit to the hair shaft including distilled white vinegar, formic acid preparations, and enzymatic nit removal systems. Using one of these agents prior to nit combing makes it easier to remove nits. Nits that are present on the hair shaft greater than 1 cm from the scalp are not considered to be viable and do not have to be removed.

Treatment of Head Lice Contacts

According to the American Academy of Pediatrics, if a case of head lice is identified, all household members should be checked for head lice. Only those with live lice or eggs within 1 cm of the scalp should be treated. It is also recommended that all hair care items and bedding belonging to the infested person be cleaned.

Chemical Lice Treatments

Chemical treatments, also known as pediculicides, vary in efficacy. It is recommended that treatment is repeated 2-3 times to ensure that lice are eliminated, and consistent use of a louse-comb is necessary. One to three days from the last treatment, hair should be checked for living lice. If nits/eggs are present, but no living lice, then treatment was successful. If living lice are present, treatment must be repeated. Pediculicides can become ineffective as lice build up tolerance to active ingredients. Sometimes several different products or alternative methods must be employed.

Natural Products For Lice Treatment

Many parents opt to use natural products as opposed to the harsh chemicals in pediculicides. Natural methods have been clinically tested and can be very effective in eradicating lice. The complexity of some natural products can actually stave off resistance. Certain plant products such as tea tree oils, coconut, neem and aniseed have proven to be effective in eliminating lice infestation in some instances. Unfortunately, no formal, structured studies have been conducted regarding natural products. One popular method involves coating your child’s head with mayonnaise, wrapping the head with plastic cling wrap and placing the child under a hair dryer.

Combs, Shaving, and Hot Air For Lice Treatment

Louse combs are effective implements to ridding the hair of lice. Combs should be used for 3-10 minutes at least, and preferably once a day if possible. Use with shampoo and conditioner is preferred. Hair should be meticulously combed through from scalp to ends several times, rinsing the comb each time to get rid of lice eggs and nits. Shaving the hair is an extremely effective option, but this can be difficult with children because of the psychological damage it can inflict. Hot air application can also be effective—there are custom built machines for this purpose.

Silicone-Based Lotions For Lice Treatment

Dimethicone is a type of silicone oil that is effective in killing lice by coating and smothering them and causing dehydration and suffocation. Dimethicone is not effective in killing nits, though, as it cannot get at their one breathing orifice. Dimethicone should be repeated after 7-10 days to ensure destruction of lice that may hatch. If dimethicone is used in combination with certain lotions and foams that can affect the breathing orifice of the nits, then it becomes even more effective as an eradication method.