Head lice are small insects that live on the scalp and glue their eggs to the hair. They spread through head-to-head contact, they do not carry disease, and they have nothing to do with how clean anyone is. Treatment clears them, but it almost always has to be repeated. Inflammation of scalp hair follicles producing itchy or tender spots.
The same eight facts on every condition comparison.
Adult lice Tan to gray insects about 2–3 mm long.
Nits on the hair Oval eggs glued close to the scalp.
Scratch marks Red bumps behind the ears and on the neck.
Scalp Folliculitis Small inflamed bumps are visible on the exposed scalp.
Head lice live among scalp hairs, feed on blood and attach their eggs to hair shafts. The body's reaction to their saliva causes itching, which may take time to develop after a first infestation.
Inflammation develops around follicles in the scalp. Bacteria, yeast, physical irritation or other contributors can be involved.
Head Lice. Most common in school-age children; close contacts of any age can be affected.
Scalp Folliculitis. Can occur at different ages after a relevant exposure or follicular inflammation.
Head lice are tiny insects that live only on the human scalp. They can't jump or fly, so they spread by crawling from one head to another.
Follicular inflammation can involve bacteria, yeast or other contributors.
Evidence labels come from each condition’s own treatment list.
The usual first treatment, applied to dry hair, left the stated time and rinsed, then repeated in seven to ten days because it does not reliably kill eggs. Where lice are not resistant it works well. Resistance to it is now common in many areas, so if two proper courses fail, the answer is a different medicine, not a third round.
The other older over-the-counter option, from chrysanthemum extract, used the same way with a repeat in seven to ten days. It kills fewer eggs than permethrin does and lice are commonly resistant to it. It is avoided in anyone with a ragweed or chrysanthemum allergy.
A silicone lotion that coats and suffocates the lice rather than poisoning them, so resistance is not an issue with it. It is left on for the stated time — often several hours or overnight — and repeated a week later. It is a good option for a child who has already failed permethrin, and it is gentle on the scalp.
Sold in several natural lice products and not shown to clear an infestation reliably. It irritates the scalp of a child who is already scratching, and it is a common cause of allergic reactions. If the older products have stopped working, a prescription treatment is a better answer than an essential oil.
Ivermectin lotion 0.5%. A single ten-minute application to dry hair, and usually no repeat is needed, because it kills the young lice as they hatch. That makes it a good choice for families who have already skipped or fumbled a second application. It is one of the main options when permethrin has failed.
Spinosad suspension. A ten-minute application to dry hair that kills both lice and most eggs, so a second treatment is often unnecessary. High cure rates in studies against permethrin-resistant lice. Cost and availability are the usual limits rather than how well it works.
Malathion lotion. An older prescription lotion that kills lice and many eggs, applied to dry hair and left on for the stated time. It works where permethrin has failed. It smells strongly, it is flammable while wet so no hairdryers, flames or cigarettes near it, and it is not used in young children.
Benzyl alcohol lotion. It works by blocking the breathing holes of the lice rather than poisoning them, so resistance is not expected. It does not kill eggs, so the repeat in seven days is essential. It can sting and irritate the scalp, which matters if the skin is already scratched.
A clinician can choose antibacterial, antifungal or anti-inflammatory treatment after assessing the pattern.
Ivermectin tablets. A tablet taken as two doses about a week apart, used when repeated topical treatments have failed or when applying a lotion to the whole scalp is not practical. It is effective in that situation. It is not used in small children or in pregnancy, so the prescriber checks weight and circumstances first.
Left alone, head lice do not clear. They cause no lasting damage; the problems come from scratching, and occasionally infection on top.
Treatment can settle inflamed follicles, but some forms recur and need maintenance. Painful deep lesions, scarring or hair loss need assessment because the course differs between scalp disorders.
Infected scalp and neck
Scratching breaks the skin, and bacteria can get in on top. The signs are redness and swelling that spreads, weeping or honey-colored crusts at the nape and behind the ears, and tender glands in the neck. It is the main reason a case of lice ever needs antibiotics, and it needs to be seen. Treating the lice properly and settling the itch early is what prevents it.
Weeks of broken sleep and worry
The lasting harm from head lice is rarely medical. It is the itching that keeps a child awake, weeks of repeat treatments and combing, missed school where old exclusion policies are still used, and the embarrassment that makes families treat it in secret. Telling the school and the other families is the single most effective thing for ending the cycle, and it is the step people most want to skip.
Scratching can cause crusting and secondary infection.
Ask a pharmacist or clinician if you cannot confirm live lice, treatment fails, or scratching causes sores or infection.
Seek care for painful deep lesions, scarring, hair loss or persistent disease.
Almost certainly direct head-to-head contact with another child — playing on the floor, a sleepover, photographs head to head. Not the house, the pets or anyone's hair. By the time you find them the contact was weeks ago.
Major pediatric and public health bodies advise against sending children home for lice. By the time they are found they have usually been there for weeks, and lice do not spread easily in a classroom. Tell the school, start treatment, and in most places the child stays. Check your school's policy — some are stricter than the guidance.
No. It makes future checks easier and reassures everyone, but empty shells are harmless and grow out. What matters is that no live lice remain. Combing with conditioner and a metal comb beats picking them out dry.
Because the itch is an allergic reaction, not the lice, and takes one to two weeks to settle after the last louse is gone. The scalp has also been scratched and treated with something drying. Itching alone is not a reason to treat again. Finding a live louse is.
Check everyone the same day and treat the ones with live lice. Some doctors also treat anyone who shares a bed, even with no live lice found, because that contact is so close. Treating the whole household regardless is not recommended.
In order of likelihood: the second application was skipped, the product was misused, someone else in the house was not treated, reinfection came from the same friend or classroom, or the lice are resistant. Only the last is a reason to change medicine, so work through the other four first.
Inflammation of scalp hair follicles producing itchy or tender spots.
Use gentle shampoo, avoid heavy oily products and do not pick the spots.
Seek care for painful deep lesions, scarring, hair loss or persistent disease.
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