What Is Head Lice?
Head lice are tiny insects that feed on the blood of the human scalp. They live on the skin located on the covering of the top of the head but can also be found in the eyebrows and eyelashes. A head lice infestation, clinically known as pediculosis, most commonly affects children, though it can affect individuals of any age. Infestations usually result from the direct transmission of lice from one infected individual's hair to another's hair. Contrary to popular belief, a head-lice infestation is not a sign of poor personal hygiene or an unclean living environment, and head lice do not carry viral or bacterial diseases.
According to the American Academy of Dermatology, millions of people get a head lice infestation each year, and they are especially common in educational environments, such as schools. Though they are not known to carry or spread diseases, head lice can make the scalp incredibly itchy, which may result in sores on the scalp that can lead to an infection. Many people may even suffer a lack of sleep due to the severity of the itchiness. If you believe you or your child has head lice, it is important to identify the signs of a head-lice infestation and to subsequently contact your dermatologist for treatment.
Where Do Head Lice Come From?
A head louse (the singular form of lice) is a tan or gray-colored insect about the size of a strawberry seed. Lice feed on human blood from humans’ scalps. Female lice firmly attach each egg to the base of a hair shaft no more than 5 millimeters from the scalp. The head lice life cycle includes three stages: lice eggs that hatch after 6–9 days, nymphs or immature forms of the louse that mature in about 9–12 days, and adult lice, which can live for 3–4 weeks. Each female louse can lay up to 6–10 eggs each day.
As with head lice in children, head lice in adults can be transmitted from one person to another through direct, head-to-head contact. This often occurs within a family or among children who have close contact at school or during playtime. Indirect transmission is less common than direct transmission, though lice can spread from one person to another through items such as hats and scarves, brushes and combs, hair accessories, headphones, pillows, towels, and upholstery. Indirect head lice transfer can also occur with items of clothing stored with clothing infected with lice. Hats, scarves, or other infected items stored in the same place can serve as transmission vehicles for lice.
Head Lice Symptoms
Common signs and head lice symptoms include itching, the presence of lice on the scalp, lice eggs on the hair shafts, and sores on the scalp, neck, and shoulders. Itching on the scalp, neck, and ears is the most common symptom of a lice infestation. Itchiness is caused by an allergic reaction to louse bites. When an individual has a lice infestation for the first time, they may not experience itchiness for 4–6 weeks after the infestation occurs. Lice can be visible to the naked eye, though they can be difficult to see as they are tiny, they avoid light, and move around the scalp quickly.
Nits, or lice eggs, stick to the shafts of hair. Nits in their incubation stage can be hard to see because of their tiny size. Eggs are easiest to see when they are located around the ears and the hairline, near the nape of the neck. Empty nits can be easier to see because they are light in color and further away from the scalp. The presence of nits, however, does not necessarily indicate a lice infestation. Severe itchiness can cause individuals to scratch their scalp, possibly leading to the development of small, red sores, which can become infected with bacteria.
Who Gets Head Lice?
Head lice can affect individuals of any age and at any time, though children and their parents are most susceptible to infestations. Because head lice are primarily spread by direct contact, the risk of transmission is greatest among young people who play together or attend the same school, particularly daycare, preschools, and elementary schools, as well as non-school locations like camps, playgrounds, and slumber parties. Dogs, cats, and other pets do not play a role in the transmission or spread of head lice.
How Is A Head Lice Infestation Diagnosed?
Diagnosing a head lice infestation is best done by finding a live nymph or adult louse on the scalp or hair. Nymphs and adult lice are very small, move quickly, and avoid light, making them difficult to spot on the scalp. You might use a magnifying glass and a fine-toothed comb to find live lice. If you do not see any lice crawling on your scalp, finding nits firmly attached to your hair shaft can suggest you have a lice infestation and should seek treatment. Nits are commonly confused with other items found in the hair, such as dandruff, hair spray residue, and dirt particles.
If no life nymphs or adult lice are found during an inspection of the scalp, and the only nits found are more than a quarter-inch from the scalp, the infestation is likely no longer active. If you are unsure whether a person has head lice, seek professional help from a dermatologist, healthcare provider, or other person trained to identify live head lice. The highest standard for diagnosing an active head-lice infestation is the identification of a live nymph or adult louse during a head lice check. During your appointment, your doctor will carefully comb your hair with a fine-toothed head lice comb from the scalp to the end of the hair. If no live louse is found, they will likely repeat the exam at a second appointment.
Head Lice Treatment
Your dermatologist will likely recommend one or more available head lice home remedies and
head lice treatment options that kill lice and some nits on the scalp. These medications might not effectively kill or get rid of recently laid eggs. As such, an appropriately timed secondary treatment may be necessary to kill nymphs after they hatch but before they have a chance to mature into adult lice. During your appointment with our Boardman dermatologists, you will receive specific instructions regarding products and medications to use, as well as a recommended treatment schedule for head lice removal.
Most over-the-counter medications for head lice are formulated with a base of pyrethrin, a chemical compound from the chrysanthemum flower toxic to lice. Before using these treatments, individuals are typically required to wash their hair with shampoo, but not conditioner. Rinsing the hair with white vinegar before washing can also help dissolve the binding agent holding nits to the hair shafts. Follow the instructions provided by your dermatologist and the written instructions on the provided medications. In some cases where lice develop resistance to over-the-counter medications, your dermatologist may recommend a prescription lice treatment, such as Ivermectin, Spinosad, or Malathion.
How To Prevent Head Lice
It can be difficult to prevent the spread of head lice, especially among children in child-care facilities and schools, due to close contact among children there. The chance of indirect transmission from personal items infested with head lice is small. But, to help prevent a head-lice infestation, you may instruct your child to hang their garments on separate hooks from other children’s garments; avoid sharing combs, brushes, hats, and scarves; and avoid lying on beds, couching, pillows, or bedding, that has been in contact with an individual who is or was infested with head lice. We also advise against sharing protective headgear for sports and bicycling, among other items that touch or are worn on the head.