Head lice are treated with a combination of topical medication and thorough combing to remove lice and their eggs. Most cases can be handled at home with over-the-counter products, though rising resistance to older treatments means you may need to try more than one approach. The key to success is following the full treatment schedule, including a second application about a week later to catch newly hatched lice before they can lay eggs of their own.
Why Two Treatments Are Necessary
No lice treatment kills every egg on the first pass. Lice eggs (called nits) are glued to individual hair shafts near the scalp and take about 8 to 9 days to hatch. The first treatment kills live, crawling lice. The second treatment, applied 7 to 9 days later depending on the product, targets any lice that hatched after the first round, catching them before they mature enough to lay new eggs. Skipping that second treatment is one of the most common reasons lice come back.
Over-the-Counter Treatments
The traditional first step is a permethrin or pyrethrin-based product, available without a prescription at most pharmacies. These have been the standard recommendation for decades, but their reliability has dropped significantly. A systematic review of global studies found that the average rate of pyrethroid resistance in lice is about 77%, and in some countries (Australia, England, Israel, and Turkey), resistance is essentially 100%. In practical terms, this means the product you pick up at the drugstore may simply not work.
If you try a permethrin-based product and still see crawling lice after the full course of treatment, that’s a sign of resistance, not a reason to keep reapplying the same product. Switch to a different class of treatment entirely.
Silicone-Based and Physical Treatments
One alternative that sidesteps the resistance problem is dimethicone, a silicone-based product sold over the counter in the U.S. as a liquid gel. Instead of poisoning lice through their nervous system the way traditional pesticides do, dimethicone works physically by coating the lice and clogging their breathing holes. Because it kills through a mechanical process rather than a chemical one, lice can’t develop resistance to it the way they have to permethrin.
In a U.S. study, 96.5% of people treated with 100% dimethicone gel were free of live lice 14 days after one to three treatments, and about 81% were also free of viable eggs. A separate study found dimethicone to be more effective than permethrin lotion. The Canadian Pediatric Society recommends dimethicone as a second-line option when standard treatments fail.
Prescription Options
When over-the-counter products don’t work, several prescription treatments are available. These use different active ingredients and mechanisms, so they remain effective against resistant lice.
- Ivermectin lotion (0.5%): Approved for ages 6 months and older. This is one of the most convenient options because it works as a single application on dry hair, and you don’t need to comb out nits afterward. Most patients are cleared with just one treatment.
- Spinosad suspension (0.9%): Also approved for ages 6 months and older. A repeat treatment is only needed if you still see live lice seven days later.
- Benzyl alcohol lotion (5%): Approved for ages 6 months and older. This one works by suffocating live lice rather than using a neurotoxin. It requires a second treatment after 7 days.
- Malathion lotion (0.5%): Approved for ages 6 and older. A second treatment is recommended if live lice are still present 7 to 9 days after the first application.
If one prescription treatment fails after a full course, your provider will typically switch to a completely different class of medication rather than repeating the same one.
Wet Combing
Combing wet hair with a fine-toothed lice comb is both a standalone treatment method and a useful companion to medication. The technique, sometimes called “bug busting,” involves applying conditioner to wet hair (which slows the lice down and makes them easier to catch), then systematically combing from root to tip, section by section, wiping the comb on a white paper towel after each stroke so you can see what you’ve removed.
As a standalone method, wet combing needs to be repeated every 3 to 4 days for at least two weeks. This cycle outlasts the hatching period of lice eggs, so each session removes newly hatched lice before they can mature. A randomized controlled trial in The Lancet found wet combing had a 38% cure rate compared to 78% for a medicated lotion, though the researchers noted that only about half of participants followed the combing schedule completely. Compliance matters: the method works better the more consistently you do it.
Even when you’re using a medicated treatment, combing out nits afterward helps in two ways. It removes dead eggs that might otherwise be mistaken for a new infestation, and it catches any live eggs the medication missed.
Home Remedies That Don’t Work
Mayonnaise, olive oil, coconut oil, and petroleum jelly are popular home remedies based on the idea of suffocating lice. The evidence for all of them is poor. These thick substances may temporarily slow lice down, making them easier to catch with a comb, but they don’t reliably kill lice and have no effect on nits. Many experts believe these treatments only stun lice rather than kill them, meaning the infestation returns once the product is washed out.
Products like gasoline, kerosene, and veterinary treatments are genuinely dangerous and should never be used on a person’s head.
Cleaning Your Home
The good news about environmental cleanup is that it doesn’t need to be extreme. Lice die within two days once they fall off a person’s head, because they can’t survive without feeding on blood. You don’t need to fumigate your house or bag up every stuffed animal for weeks.
Focus on items that touched the infested person’s head in the two days before treatment. Machine wash and dry clothing, towels, pillowcases, and bed linens using hot water (at least 130°F) and the high-heat dryer cycle. For items that can’t be washed, sealing them in a plastic bag for two weeks will ensure any lice or nits on them are dead. Vacuum upholstered furniture and car seats. Soak combs, brushes, and hair accessories in hot water for 5 to 10 minutes.
Checking the Whole Household
If one family member has lice, everyone in the household should be checked, but only people with live lice or eggs found within about a centimeter of the scalp need treatment. Treating people “just in case” wastes medication and exposes them to chemicals unnecessarily. Anyone who shares a bed with the infested person is reasonable to treat even without confirmed lice, since the close, prolonged contact makes transmission very likely.
Children with lice should stay in school for the rest of the day and begin treatment that evening. The American Academy of Pediatrics’ position is that a child should not miss class time over head lice. After proper treatment, they can return with the simple instruction to avoid direct head-to-head contact with other kids.
Safety Tips for Treatment
An adult should always apply lice medication. Children should never handle the products themselves. Rinse the treatment off over a sink rather than in the shower or bath, so it doesn’t run down onto skin where it isn’t needed. Only use lice medication when you’ve confirmed live lice are present, not as a preventive measure. If the first treatment doesn’t work and you’re considering switching to a different product, that’s a good time to check in with a healthcare provider to make sure you’re choosing the right next step for your child’s age.