Head Lice in Children: A Pediatrician’s Complete Guide to Treatment & Prevention

What Are Head Lice?

Head lice (Pediculus humanus capitis) are tiny, wingless parasitic insects about the size of a sesame seed that live on the human scalp and feed on small amounts of blood. They are gray, tan, or brown in color. Nits are their eggs — tiny oval specks firmly cemented to individual hair shafts, usually within a centimeter of the scalp.

Head lice are extremely common. The CDC estimates that 6–12 million infestations occur in the United States each year, the vast majority in children aged 3–11. Lice do not carry disease. Having head lice is not a sign of poor hygiene or an unclean home — lice have no preference for dirty hair over clean hair.

How Do Children Get Head Lice?

Head lice spread almost exclusively through direct head-to-head contact with a person who has lice. They cannot jump or fly. Indirect spread through shared hats, helmets, hair accessories, headphones, pillowcases, or upholstered furniture is possible but much less common — lice survive only 1–2 days off the human scalp.

The most common transmission settings are homes, schools, daycares, sleepovers, sports teams, and camps — any environment where children’s heads come into close proximity.

How to Check Your Child’s Hair for Head Lice

Checking requires good lighting and a fine-toothed nit comb. Follow these steps:

• Wet the hair and apply a generous amount of conditioner — this slows lice movement and makes combing easier.
• Work through the hair in small sections, starting at the scalp, using a fine-toothed nit comb. Wipe the comb on a white paper towel after each stroke.
• Examine the paper towel and the hair under bright light. Lice are small (sesame seed-sized), gray or tan, and move quickly when exposed to light. Nits look like tiny white or yellow-tan oval specks glued to individual hair shafts — they do not flick off easily the way dandruff does.
• Pay particular attention to the nape of the neck, behind the ears, and the crown — these are the most common locations.
• Repeat the combing process every 2–3 days during and after treatment for 2–3 weeks.

The most common symptom of head lice is itching of the scalp, particularly at the back and behind the ears — but itching may not develop for 4–6 weeks after an infestation begins. Some children never itch at all. Do not rely on itching alone to rule out lice.

Head Lice Treatment: What Actually Works

There are two categories of head lice treatment: over-the-counter (OTC) and prescription. Start with OTC treatment for most cases.

Step-by-Step: Using Permethrin 1% (Nix) — the OTC First-Line Treatment

Follow these steps exactly — the second application is just as important as the first:

• Step 1: Wash the hair with regular shampoo (no conditioner) and towel-dry so the hair is damp but not dripping.
• Step 2: Apply permethrin 1% shampoo thoroughly from roots to ends. Make sure all hair and scalp areas are covered.
• Step 3: Leave on for exactly 10 minutes (set a timer).
• Step 4: Rinse thoroughly with warm water.
• Step 5: Use a fine-toothed nit comb to comb through the hair in sections, removing dead lice and nits. Work under good lighting.
• Step 6: Repeat the entire process in exactly 9 days — this kills any lice that have hatched from eggs that survived the first treatment.
• Step 7: Continue checking hair every 2–3 days for the following 2 weeks to confirm all lice have been eliminated.

Important: If you still see live (moving) lice 8–12 hours after treatment, the product may not be working — this can indicate resistance. Call Spring Valley Pediatrics at 202-966-5000. Do not reapply the same product more frequently than directed — resistance, not insufficient product, is usually the cause.

Nit Combing: How to Do It Correctly

Nit combing is essential alongside any treatment. Even dead nits remain attached to the hair and can be confused for live infestation.

• Use a metal fine-toothed nit comb — plastic combs from OTC kits are often less effective.
• Wet the hair and apply conditioner generously before combing — this slows movement of live lice and lubricates the hair.
• Work in 1-inch sections from scalp to ends. After each stroke, wipe the comb on a white paper towel to check for lice and nits.
• Pay close attention to the hairline at the nape of the neck and behind the ears.
• Repeat combing every 2–3 days for at least 2–3 weeks after the last live louse is found.

Cleaning the Home: What’s Necessary and What’s Not

The amount of home cleaning required is often overstated. Because lice cannot survive more than 1–2 days off a human scalp, extensive environmental decontamination is not necessary. Here is what is actually useful:

Do These

• Wash bedding, pajamas, recently worn clothing, hats, and scarves in hot water (130°F or higher) and dry on high heat for at least 20 minutes.
• Vacuum upholstered furniture and car seats where the child’s head rests.
• Seal items that cannot be washed in a plastic bag for 2 weeks (lice cannot survive more than 48 hours off the scalp).
• Soak combs, brushes, and hair accessories used by the infested child in hot water (130°F) for 5–10 minutes, or replace them.
• Check all household members for head lice. Treat only those in whom live lice or viable nits are found.

Skip These (Not Necessary)

• Fumigant sprays — these are not recommended by the AAP and are potentially harmful, particularly to children and pets.
• Vacuuming every surface in the house — lice do not survive on floors or most surfaces.
• Replacing mattresses, furniture, or pillows.
• Keeping your child home from school for extended periods — see school policy section below.

School and Daycare: When Can My Child Return?

The American Academy of Pediatrics and the National Association of School Nurses have moved away from “no-nit” policies. Current guidance:

• Children should not be sent home from school in the middle of the day because lice are found.
• Children who have been treated do not need to be kept home from school — they can return after the first treatment has been completed.
• The presence of nits after treatment does not require exclusion from school.
• Check with your specific school — policies vary. Some DC-area schools still follow older no-nit policies.

The primary goal is prompt treatment, not exclusion. Lice are not a health hazard and do not spread disease.

When to Call Spring Valley Pediatrics

• Two rounds of permethrin 1% (Nix) have not eliminated the infestation — prescription treatment is needed.
• You are unsure whether what you see is lice or nits versus dandruff or hair product residue.
• Your child develops a scalp infection — signs include increasing redness, warmth, crusting, or swelling of the scalp or lymph nodes in the neck.
• Your child is under 2 years old — some OTC products are not appropriate for very young children.
• A household member with a weakened immune system has been exposed.

Call us at 202-966-5000. We see lice-related concerns at same-day sick visits and can prescribe effective single-dose prescription treatments when OTC products have not worked.

Head Lice Prevention

There is no reliably effective way to prevent all lice exposure. The following practical steps reduce risk:

• Teach children to avoid head-to-head contact during play, sleepovers, and sports.
• Discourage sharing of hats, helmets, hair accessories, headphones, pillows, and towels.
• Long hair worn up (in a braid, bun, or ponytail) during school reduces contact surface area.
• Check your child’s hair monthly during the school year, and immediately if you receive a lice notification from school.
• Tea tree oil, lavender oil, and other “natural” repellents have not been proven effective in controlled studies — they are not recommended as reliable prevention.