Head lice

In most cases, head lice are not immediately noticed after infestation. The eggs laid by head lice are called nits. Intense itching on the head and the appearance of nits indicate the presence of head lice. Some common signs and symptoms include:

• Itching or the urge to scratch
• Tingling or a crawling sensation, akin to the feeling of something moving in the hair
• Difficulty sleeping due to itching, as lice are active at night
• Red sores on the head, neck, and shoulders (caused by scratching)
• Swollen lymph nodes

Head lice and their eggs are most frequently observed by looking closely near the hair root. They are commonly found behind the ears and the upper part of the back of the neck. Rarely, they may be seen on the eyelashes, eyebrows, or beard.

A head louse (plural is lice) is a tan or grayish, tiny six-legged insect about the size of a flax seed. It clings to the scalp and hair and feeds on human blood.

The lice eggs or nits hatch into nymphs, which become full-grown lice. Adult lice mate to produce more nits. The three stages of the life cycle are explained in detail:

• Lice Eggs or Nits: Nits are firmly attached to the hair shaft by a glue-like sticky substance produced by a female louse. They are usually yellow or white in color, oval in shape, and 2-3 mm in length. Nits take about six to nine days to hatch. They are not easily visible and are often confused with dandruff.
• Nymphs: A nit hatches into a small louse called a nymph. The nymphs require human blood for survival and mature into adults in about seven to ten days after hatching.
• Adult lice: Adults have a life span of about one month. The female lays 6 to 10 eggs a day and is usually larger than males. If the louse falls off a person and does not get human blood, it dies within a day or two.

While most people think head lice are caused by unclean hair and scalp, this is not true. Having head lice is not a sign of poor personal hygiene or an unclean living environment. Head lice do not carry bacterial or viral infections. They feed on blood and can affect almost anyone.

However, girls are known to be more at risk than boys for infection because they tend to have more head-to-head contact. Additionally, girls with long, thick, and curly hair may find it difficult to combat lice infestations as it makes locating the parasites more challenging.

Head lice cannot jump or fly; they can only crawl. Therefore, transmission from one person to another usually occurs through direct head-to-head contact. This is often seen within families or among children who have close contact in schools, playgroups, etc.

Indirect transmission is not very common, but one may be at risk of getting head lice while sharing items such as:

• Combs
• Hats or scarves
• Towels
• Helmets
• Bedding
• Hair brushes or hair accessories
• Headphones
• Clothes

As head lice are approximately 2-3 mm long and can tightly grip hair strands while crawling, locating them in the hair can be challenging. The most effective method for detection is through combing and manual examination.

• Thoroughly comb wet hair with a fine-tooth comb, focusing on the back of the head where lice are commonly found.
• Conduct a manual examination of the hair to identify nits attached to the base of hair shafts. Nits may resemble dandruff or dirt. Attempt to pull the small speck with your fingers; while dandruff and dirt can be easily removed, nits typically remain stuck. Finding a nymph or adult louse can be difficult due to their rapid movement.

The first and foremost tip to keep in mind is that there is no effective method to prevent head lice. However, there are ways to stop the spread of head lice from one person to another. If anyone in your family suffers from head lice, here are a few tips to follow:

• Wash clothes, bedding, and towels in hot water and dry them on the hottest setting.
• Opt for dry cleaning if you cannot wash these items at home.
• Use a vacuum to clean furniture, carpets, and car seats.
• Items that cannot be washed, such as soft toys and pillows, should be placed in a plastic bag and sealed for at least two weeks.
• Avoid sharing a bed with a person infested with lice, as there is a high possibility of lice being transferred through direct head-to-head contact.
• Do not use the combs, brushes, and hair care products used by a person who has head lice.
• It is advisable to throw away or sterilize items for future use.
• Do not send your child to school if he or she has head lice.

Once lice have settled on your scalp, they do not go away on their own. In most cases, treatment is aimed at killing the parasites by suffocating them.

Some of the common over-the-counter treatment options for head lice include:

• Pyrethrin: An over-the-counter medicine that contains naturally occurring pyrethroid extracts. It can kill only live lice and not nits (unhatched eggs). A second treatment after 9 to 10 days of the first treatment is recommended to kill newly hatched lice and prevent them from producing new eggs. Approved for use in children above 2 years.
• Permethrin: A synthetic form of naturally occurring pyrethrin extracts. Permethrin lotion 1% is an FDA-approved product for the treatment of head lice. It is safe and effective when used according to doctor's advice. Like pyrethrin, it kills live lice but not unhatched eggs, so a second dose is recommended after 9 to 10 days.

Some of the common prescription medications for head lice include:

• Benzyl alcohol lotion, 5%: An FDA-approved product for head lice treatment, found to be safe and effective when used as directed by a doctor. It kills lice but not unhatched eggs, so a second treatment after 7 days of the first is recommended.
• Ivermectin lotion, 0.5%: This formulation prevents newly hatched lice from surviving. It is effective when applied to dry hair without nit combing. It can be applied once to dry hair and rinsed with water after 10 minutes. Ivermectin is also available as a tablet and can be taken if other topical treatments fail to eliminate lice.
• Malathion lotion, 0.5%: Known to kill lice and some eggs. A second treatment after 7 to 9 days of the first is advised for enhanced effectiveness. Recommended for use in children above 6 years. As this lotion is flammable, it is not advisable to use electrical devices such as hair dryers after application or when the hair is wet.
• Spinosad 0.9% topical suspension: Kills both live lice and unhatched eggs, hence retreatment is not required. Nit combing is also not necessary. Approved for the treatment of children above 6 months.
• Lindane shampoo 1%: Usually recommended as a second-line treatment only, as overuse or misuse can cause toxic side effects on the brain and nervous system. Not advised for treatment in individuals with HIV, seizure disorders, pregnant or breastfeeding women, and those with skin sores. Retreatment is strictly not recommended.

Here are some tips to deal with head lice at home:

• Wet combing is usually preferred to remove lice from hair for young children. Use a regular brush or comb to remove tangles from wet hair before using a special comb.
• Use a special fine-toothed comb to carefully comb out nits and lice from hair. Pull the comb through the hair from roots to ends. Comb the entire head at least twice.
• The nits (lice eggs) mature in 5-7 days, so it is important to comb every day for about 2 weeks to ensure you get rid of all the lice.
• You can get a prescription for kids if combing doesn’t work and the infestation is severe.
• Beware of using natural remedies like olive oil or butter and toxic substances such as kerosene to get rid of head lice, as these might cause more harm than good.

Head lice, if left untreated, can lead to severe itching and scratching of the scalp. If a person scratches an itchy scalp due to a head lice infestation, it is possible for the skin to break and develop an infection. In the worst-case scenario, a visit to a dermatologist may be necessary to treat a secondary bacterial infection of the skin resulting from head lice.

A number of household products are commonly used for the treatment of head lice. However, do not use natural remedies such as:

• Olive oil
• Butter
• Petroleum jelly
• Mayonnaise

These remedies are believed to work by suffocating the lice, but they are ineffective as lice are difficult to suffocate.

Avoid using toxic compounds like gasoline and kerosene due to the risks associated with lice. There is no research evidence supporting their effectiveness, and their use can lead to serious injury.

Head lice can be very annoying, but they are not dangerous and do not spread any disease. They are also not a sign of poor hygiene. Head lice require blood for survival, which is not dependent on the hygiene of the head or surroundings. They can be managed through various treatment options and additional measures, including:

• Do not use combs, hair brushes, hats, bedding, towels, or clothing of a person affected by head lice.
• The lice and eggs can be removed to some extent with the help of a very fine-toothed comb on wet hair.
• Medication includes pediculicides (medications that kill lice) with ovicidal effects (which kill nits or unhatched eggs), which is the most important treatment.
• To prevent reinfestation, nits are killed by using hot air (slightly cooler than a hair dryer) for 30 minutes.
• Wash all clothes, bedding, and combs in hot water with detergent.
• Repeat treatment after 7 to 10 days.