Head Lice

What are head lice?

From: MedlinePlus, National Library of Medicine

Head lice are tiny insects that live on people's heads. Adult lice are about the size of sesame seeds. The eggs, called nits, are even smaller - about the size of a dandruff flake. Lice and nits are found on or near the scalp, most often at the neckline and behind the ears.

Head lice are parasites, and they need to feed on human blood to survive. They are one of the three types of lice that live on humans. The other two types are body lice and pubic lice. Each type of lice is different, and getting one type does not mean that you will get another type.

How do head lice spread?

From: MedlinePlus, National Library of Medicine

Lice move by crawling, because they cannot hop or fly. They spread by close person-to-person contact. Rarely, they can spread through sharing personal belongings such as hats or hairbrushes. Personal hygiene and cleanliness have nothing to do with getting head lice. You also cannot get pubic lice from animals. Head lice do not spread disease.

Who is at risk for head lice?

From: MedlinePlus, National Library of Medicine

Children ages 3-11 and their families get head lice most often. This is because young children often have head-to-head contact while playing together.

What are the symptoms of head lice?

From: MedlinePlus, National Library of Medicine

The symptoms of head lice include:

• Tickling feeling in the hair
• Frequent itching, which is caused by an allergic reaction to the bites
• Sores from scratching. Sometimes the sores can become infected with bacteria.
• Trouble sleeping, because head lice are most active in the dark

How do you know if you have head lice?

From: MedlinePlus, National Library of Medicine

A diagnosis of head lice usually comes from seeing a louse or nit. Because they are very small and move quickly, you may need to use a magnifying lens and a fine-toothed comb to find lice or nits.

What are the treatments for head lice?

From: MedlinePlus, National Library of Medicine

Treatments for head lice include both over-the-counter and prescription shampoos, creams, and lotions. If you want to use an over-the-counter treatment and you aren't sure which one to use or how to use one, ask your health care provider or pharmacist. You should also check with your health care provider first if you are pregnant or nursing, or if you want to use a treatment on a young child.

Follow these steps when using a head lice treatment:

• Apply the product according to the instructions. Only apply it to the scalp and the hair attached to the scalp. You should not use it on other body hair.
• Use only one product at a time, unless your health care provider tells you to use two different kinds at once
• Pay attention to what the instructions say about how long you should leave the medicine on the hair and on how you should rinse it out
• After rinsing, use a fine-toothed comb or special "nit comb" to remove dead lice and nits
• After each treatment, check your hair for lice and nits. You should comb your hair to remove nits and lice every 2-3 days. Do this for 2-3 weeks to be sure that all lice and nits are gone.

All household members and other close contacts should be checked and treated if necessary. If an over-the-counter treatment does not work for you, you can ask your health care provider for a prescription product.

Can head lice be prevented?

From: MedlinePlus, National Library of Medicine

There are steps you can take to prevent the spread of lice. If you already have lice, besides treatment, you should:

To prevent your children from spreading lice:

There is no clear scientific evidence that lice can be suffocated by home remedies, such as mayonnaise, olive oil, or similar substances. You also should not use kerosene or gasoline; they are dangerous and flammable.

• Wash your clothes, bedding, and towels with hot water, and dry them using the hot cycle of the dryer
• Soak your combs and brushes in hot water for 5-10 minutes
• Vacuum the floor and furniture, particularly where you sat or lay
• If there are items that you cannot wash, seal them in a plastic bag for two weeks
• Teach children to avoid head-to-head contact during play and other activities
• Teach children not to share clothing and other items that they put on their head, such as headphones, hair ties, and helmets
• If your child has lice, be sure to check the policies at school and/or daycare. Your child may not be able to go back until the lice have been completely treated.

Which doctor should you see?

The suggested department for discussing Head Lice is Infectious Diseases, with a general physician / infectious disease specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which exposure or organism is suspected, and what evidence would confirm it?
• Are precautions, vaccination or advice for close contacts relevant to this infection?
• What should happen if symptoms worsen or do not improve as expected?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.