What should you do if lice appear?

Understanding Head Lice

What Are Head Lice?

Head lice (Pediculus humanus capitis) are tiny, wing‑less insects that live on the human scalp. Adults measure 2–4 mm, are tan to gray, and cling to hair shafts with clawed legs. Nymphs, or “nymphs,” hatch from eggs (nits) and mature in about seven days, undergoing three molts before reaching adulthood. A single female can lay up to 10 eggs per day, resulting in rapid population growth if untreated.

Lice feed exclusively on human blood, inserting a short proboscis into the scalp to draw small amounts of blood several times a day. Their bite may cause itching, redness, and secondary skin irritation from scratching. Lice cannot survive more than 48 hours off a human host, but nits remain viable for up to a week attached to hair shafts.

Transmission occurs primarily through direct head‑to‑head contact, which explains higher prevalence among school‑aged children. Indirect spread via personal items—combs, hats, pillows—is possible but less common. Lice do not transmit disease; their main impact is discomfort and potential social stigma.

Key identification points:

Live insects moving quickly on the scalp.
Small, oval nits firmly attached to hair close to the scalp, often mistaken for dandruff.
Intense itching that intensifies after several days of infestation.

How Do You Get Lice?

Lice infestations arise primarily through direct head‑to‑head contact, which transfers live insects or their eggs from one scalp to another. Indirect transfer can occur when hair accessories, hats, helmets, or bedding that have recently touched an infested head are shared without proper cleaning.

Close personal interaction, such as play or sports activities, where heads touch
Borrowed items: combs, brushes, hair clips, scarves, or earmuffs
Shared sleeping surfaces: pillows, blankets, or mattresses
Clothing or headgear stored together in confined spaces (e.g., lockers, dormitory closets)

Additional factors increase the likelihood of acquisition: crowded environments, infrequent laundering of personal items, and inadequate inspection of children’s hair after group activities. Understanding these transmission routes guides effective prevention and prompt response when lice are detected.

Symptoms of a Lice Infestation

Itching and Scalp Irritation

Itching and scalp irritation indicate a lice infestation, resulting from an allergic response to the insects’ saliva. The sensation often intensifies after several days of feeding and can lead to secondary skin damage if left unchecked.

Immediate measures reduce discomfort and limit further irritation:

Apply a medicated lice treatment according to the product label; most contain permethrin or pyrethrin, which kill both lice and nits.
Use a gentle, anti‑itch shampoo containing zinc pyrithione or tea‑tree oil to soothe inflamed skin.
Rinse the hair with lukewarm water; avoid hot water, which can exacerbate itching.
Refrain from scratching; use a soft brush to remove loose debris and reduce the risk of infection.

After treatment, monitor the scalp for persistent redness or swelling. If symptoms persist beyond 48 hours, repeat the application as directed or seek professional medical advice. Persistent inflammation may require topical corticosteroids or antihistamines prescribed by a healthcare provider. Continuous observation ensures that the irritation resolves and that the infestation is fully eradicated.

Visible Lice or Nits

Visible lice or nits signal an infestation that requires immediate action. Examine the scalp closely, using a fine-toothed comb on damp hair, to confirm the presence of live insects or attached eggs. Once confirmed, follow these steps:

Apply a recommended pediculicide according to the product label; allow the specified contact time before rinsing.
Repeat the treatment after seven to ten days to eliminate newly hatched lice that survived the first application.
Comb the hair with a nit comb at least twice daily for a week, removing all visible nits and dead insects.
Wash bedding, clothing, and personal items in hot water (minimum 130 °F/54 °C) and dry on high heat; seal untouched items in a sealed plastic bag for two weeks.
Vacuum carpets, upholstery, and car seats to remove stray lice and nits; discard vacuum bags promptly.
Inform close contacts—family members, classmates, caregivers—so they can inspect and, if necessary, treat themselves.

Monitor the scalp for a further two weeks. Persistent signs of lice after the second treatment indicate a possible resistance; consult a healthcare professional for alternative options.

Immediate Actions Upon Discovering Lice

Confirming the Infestation

Visual Inspection

Visual inspection is the first critical step when lice are suspected. Examine the scalp and hair carefully under bright light. Use a fine-toothed comb, preferably a lice comb, to separate strands and reveal any nits or live insects. Focus on the areas most likely to harbor lice: behind the ears, at the nape of the neck, and near the hairline.

During the examination:

Part hair into small sections, pulling each segment taut.
Scan each section from root to tip, looking for oval, white‑to‑tan eggs attached to the hair shaft.
Identify live lice, which appear as small, brownish insects about the size of a sesame seed, moving quickly when disturbed.
Record the number and location of findings to assess infestation severity.

If any nits or lice are found, proceed immediately with treatment measures and repeat visual checks after 7–10 days to confirm eradication. Regular inspections, conducted every few days during treatment, ensure that residual eggs are detected and removed promptly.

Using a Lice Comb

A fine‑toothed lice comb removes live insects and eggs from the hair shaft. The metal or plastic teeth must be close enough to capture nits but spaced to glide through wet, conditioned hair without breaking strands.

Wet the hair with a regular shampoo; rinse and leave a generous amount of conditioner to reduce slip.
Section the scalp into manageable strips using clips or a tail comb.
Starting at the scalp, pull the comb through each section from root to tip in a slow, steady motion.
After each pass, wipe the comb on a tissue and rinse it in warm water to dislodge captured lice and nits.
Repeat the process on every section, then rinse the hair thoroughly.
Perform the combing routine every 2–3 days for two weeks, or until no live lice or nits are detected.

Consistent use of the comb, combined with proper hair preparation, eliminates the infestation without chemicals and minimizes the risk of reinfestation.

Informing Close Contacts

When head lice are detected, immediate notification of people who share living space, classrooms, or personal items is essential. Prompt communication limits the spread and allows others to begin preventive measures without delay.

Identify all individuals who have had direct head‑to‑head contact with the affected person during the past two weeks.
Inform each person personally, providing clear details about the situation and the need for inspection.
Recommend that contacts examine hair and scalp for live insects or viable eggs, using a fine‑toothed comb.
Advise immediate treatment for anyone who tests positive, following the same regimen used for the original case.
Suggest washing clothing, bedding, and personal items in hot water (≥130 °F) and drying on high heat, or sealing them in a plastic bag for two weeks if washing is not possible.

Consistent, factual alerts enable families, schools, and caregivers to act quickly, reducing the risk of a wider outbreak.

Preventing Further Spread

When lice are detected, immediate actions must focus on halting transmission to other individuals and environments.

Separate the affected person from close contact for at least 24 hours while treatment is applied.
Apply a recommended pediculicide to the scalp and follow the product’s timing instructions precisely.
Comb wet hair with a fine‑toothed lice comb every 2–3 days for two weeks, removing each nymph and egg.
Wash all clothing, bedding, and towels used in the previous 48 hours in water ≥ 130 °F (54 °C) or dry‑clean them.
Seal non‑washable items in sealed plastic bags for two weeks to deprive lice of a host.
Vacuum carpets, upholstery, and vehicle seats; discard vacuum bags or empty canisters immediately.
Inform schools, daycare centers, or other groups the person interacts with, providing details of treatment dates and preventive measures.
Instruct family members and close contacts not to share combs, hats, helmets, or headphones until a full treatment cycle is completed.

Continued vigilance—regular head checks and prompt re‑treatment if any live lice reappear—ensures the infestation does not re‑establish and protects the broader community.

Treatment Options for Head Lice

Over-the-Counter Lice Treatments

Permethrin-Based Products

Permethrin‑based treatments are the most widely recommended first‑line option for eliminating head lice. The active ingredient, permethrin, is a synthetic pyrethroid that disrupts the nervous system of lice, leading to rapid paralysis and death. Products containing 1 % permethrin are available as shampoos, lotions, or sprays and are approved for use on children over two months of age.

Application guidelines:

Apply the product to dry hair, saturating the scalp and shafts from root to tip.
Leave the preparation on for the time specified in the label, typically 10 minutes.
Rinse thoroughly with lukewarm water; avoid hot water, which can reduce efficacy.
Comb the hair with a fine‑toothed nit comb immediately after rinsing to remove dead insects and eggs.
Repeat the treatment after 7–10 days to target newly hatched nymphs that survived the first application.

Safety considerations:

Do not use on infants younger than two months or on individuals with a known allergy to permethrin or other pyrethroids.
Avoid contact with eyes; if irritation occurs, rinse with water and seek medical advice.
Do not combine with other insecticidal products, as this may increase the risk of adverse reactions.

Resistance monitoring:

Reports of permethrin‑resistant lice populations exist in some regions; if treatment fails after two applications, consider an alternative agent such as a silicone‑based lotion or a prescription oral medication.
Confirm proper dosing and thorough combing before concluding that resistance is present.

Environmental precautions:

Dispose of used applicators and leftover product according to local regulations to prevent accidental exposure to pets or wildlife.
Wash clothing, bedding, and personal items in hot water (≥ 130 °F) and dry on high heat to eliminate residual lice or eggs.

Following these steps maximizes the likelihood of successful eradication while minimizing side effects and the chance of re‑infestation.

Pyrethrin-Based Products

When head lice are detected, immediate treatment is essential to prevent spread and re‑infestation. Pyrethrin‑based products constitute a primary option for rapid eradication.

Pyrethrins are natural insecticidal compounds extracted from chrysanthemum flowers. They affect the nervous system of lice, causing paralysis and death within minutes of contact. Formulations typically combine pyrethrins with piperonyl butoxide, a synergist that enhances penetration of the active ingredient.

Effective use requires strict adherence to the label:

Apply the product to dry, combed hair, ensuring coverage from scalp to hair tips.
Leave the preparation on for the recommended duration, usually 10 minutes.
Rinse thoroughly with warm water.
After 7–10 days, repeat the application to eliminate newly hatched nymphs.
Use a fine‑toothed nit comb on each treatment day to remove dead insects and eggs.

Safety considerations include:

Avoid use on children under two months or on individuals with known sensitivity to pyrethrins.
Do not apply to irritated or broken scalp skin.
Wash hands and clothing after treatment to prevent accidental exposure.

Resistance to pyrethrins has been documented in some regions. If lice persist after two full treatment cycles, switch to a non‑pyrethrin option, such as a dimethicone‑based lotion, and consult a healthcare professional for guidance.

Prescription Lice Treatments

Malathion Lotion

When an infestation of head lice is detected, immediate eradication is required to prevent spread and discomfort. Chemical treatments constitute the primary method of control, and Malathion Lotion is a widely recognized option.

Malathion Lotion contains 0.5 % malathion, an organophosphate insecticide that paralyzes lice by disrupting their nervous system. The product is applied to dry hair, ensuring full coverage from scalp to tips. Recommended exposure time is eight hours, after which the hair should be washed with regular shampoo. The lotion is safe for children aged six months and older, provided the scalp is intact and no allergic reactions to insecticides are known. Contraindications include open wounds, eczema, or known hypersensitivity to malathion. Use of protective gloves during application minimizes skin contact.

Effective use of Malathion Lotion incorporates the following steps:

Separate hair into sections; apply lotion with a fine-tooth comb or spray bottle.
Cover treated area with a shower cap to maintain moisture and prevent evaporation.
After the eight‑hour interval, rinse thoroughly; repeat the process seven days later to eliminate newly hatched nymphs.
Comb wet hair with a fine-tooth lice comb to remove dead insects and nits.
Launder clothing, bedding, and personal items in hot water (≥ 130 °F) or seal them in plastic bags for two weeks.

Adhering to the dosage schedule and post‑treatment combing maximizes the likelihood of complete eradication while reducing the risk of resistance development.

Ivermectin Lotion

Ivermectin lotion is a topical antiparasitic medication approved for the treatment of head‑lice infestations. The active ingredient, ivermectin, binds to glutamate‑gated chloride channels in the parasite’s nervous system, causing paralysis and death of the lice.

When lice are detected, consider the following protocol with ivermectin lotion:

Verify that the product is labeled for head‑lice use and that the patient’s age meets the minimum requirement (typically 6 months or older, depending on the formulation).
Apply the lotion to dry hair and scalp, covering all affected areas. Follow the manufacturer’s recommended amount, generally a few milliliters per square centimeter of scalp.
Leave the lotion on for the specified contact time, usually 10 minutes, then rinse thoroughly with water.
Repeat the application after 7 days to eliminate any newly hatched lice that survived the first treatment.
Perform a manual combing with a fine‑toothed lice comb after each application to remove dead insects and eggs.

Safety considerations include:

Avoid use on broken or inflamed skin.
Do not apply to children below the approved age or to individuals with known hypersensitivity to ivermectin.
Common adverse effects are mild scalp irritation, itching, or redness; severe reactions are rare but require medical attention.

Ivermectin lotion offers an alternative to traditional pediculicides such as permethrin, particularly in cases where resistance to those agents is documented. Availability is typically through pharmacies with a prescription in many regions; over‑the‑counter options may exist in some markets.

If lice are present, initiating treatment with ivermectin lotion, adhering to the dosing schedule, and complementing it with thorough combing provides an effective strategy to eradicate the infestation.

Non-Chemical Treatments

Wet-Combing Method

Wet‑combing is a proven mechanical technique for eliminating head‑lice infestations without chemicals. The method relies on a fine‑toothed, metal comb to capture live lice and their eggs while the hair remains damp, which immobilizes the insects and improves grip.

Prepare a bowl of warm water and add a small amount of conditioner to reduce friction.
Saturate the scalp and hair, then towel‑dry until hair is damp but not dripping.
Starting at the scalp, run the comb through a small section of hair in a slow, steady motion toward the ends.
After each pass, wipe the comb on a tissue and rinse it in the water before continuing.
Repeat the process for the entire head, ensuring every strand is examined.

Complete the session by washing the comb with soap and hot water. Repeat the wet‑combing routine every three to four days for a minimum of two weeks, or until a thorough inspection shows no live lice or viable nits. Maintaining clean bedding, hats, and personal items reduces the risk of re‑infestation.

Suffocation Treatments (e.g., Mayonnaise, Petroleum Jelly)

Suffocation treatments rely on coating the scalp and hair with a thick, oily substance to block the lice’ ability to breathe. Common agents include mayonnaise and petroleum jelly, both readily available and inexpensive.

To apply a suffocation remedy, follow these steps:

Wash hair with a mild shampoo; avoid conditioner.
Pat hair dry until it is damp but not wet.
Generously spread mayonnaise or petroleum jelly from roots to tips, ensuring every strand is covered.
Cover the head with a plastic shower cap or cling‑film to prevent the product from drying.
Leave the coating in place for 6–8 hours, preferably overnight.
Remove the cap, wash hair thoroughly with warm water and shampoo to eliminate the oily residue.
Comb hair with a fine‑toothed lice comb to extract dead insects and nits.
Repeat the process after 7 days to target any newly hatched lice.

Effectiveness depends on maintaining a continuous barrier; gaps allow some lice to survive. Studies show a single application reduces live lice by 70‑80 %, while a second treatment increases eradication to over 90 %.

Safety considerations include the risk of skin irritation, especially in children with sensitive scalps. Apply only to dry hair; avoid contact with eyes. Petroleum jelly is flammable, so keep away from open flames. For individuals with allergies to egg products, mayonnaise should be avoided.

Suffocation methods complement mechanical removal and can be part of an integrated approach when lice are detected.

After Treatment: Follow-Up and Prevention

Post-Treatment Hair Care

After the lice have been eradicated, maintaining clean, well‑conditioned hair reduces the chance of a new infestation and supports scalp recovery.

Wash the hair with a mild, sulfate‑free shampoo. Rinse thoroughly to remove residual treatment chemicals.
Apply a lightweight conditioner to the mid‑lengths and ends only; avoid the scalp to prevent excess moisture that attracts insects.
Use a fine‑tooth lice comb on damp hair. Start at the roots and work toward the tips, cleaning the comb after each pass.
Dry the hair completely with a low‑heat setting. Damp hair creates an environment conducive to lice survival.
Separate long hair into sections and secure each with a clean elastic band or hair clip while combing, ensuring thorough coverage.
Inspect the scalp and hair daily for one week. Record any live insects or nits; repeat combing if needed.

In addition to hair care, disinfect personal items that contacted the head. Wash pillowcases, hats, brushes, and combs in hot water (≥60 °C) and dry on high heat. Store unused hair accessories in sealed containers until the monitoring period ends.

Following these measures restores hair health and minimizes the risk of recurrence.

Cleaning Your Home Environment

Washing Bedding and Clothing

When lice are detected, treat all bedding, towels, and sleepwear as contaminated. Wash items in water ≥ 130 °F (54 °C) for at least 10 minutes; this temperature kills lice and their eggs. If the fabric cannot withstand high heat, place items in a sealed plastic bag for two weeks, a period that exceeds the lice life cycle, then launder on the hottest setting the material permits.

Separate infected laundry from other household items.
Use a high‑temperature wash cycle; add a disinfectant if recommended by the manufacturer.
Dry on the highest heat setting for a minimum of 30 minutes.
For items that cannot be machine‑washed, seal in airtight containers for 14 days before use.
Clean washing machine drums with a hot water rinse after the cycle.

Clothing that contacts the head, such as hats, scarves, and uniforms, requires the same washing protocol. Items that are dry‑clean only should be taken to a professional cleaner and labeled as containing lice. After laundering, store clean bedding and clothing in a clean, dry area to prevent re‑infestation.

Vacuuming and Cleaning Surfaces

When lice are detected in a household, removing eggs and nits from the environment reduces the risk of re‑infestation. Vacuuming carpets, rugs, and upholstery extracts detached lice and dislodged eggs that may have fallen from hair. Use a high‑efficiency bag or empty the canister immediately after each session to prevent escape.

Cleaning surfaces eliminates viable lice that could survive for a short period. Follow these actions:

Vacuum floors, under furniture, and in crevices; discard the vacuum bag or clean the filter with hot, soapy water.
Wipe hard surfaces—countertops, tables, door handles, and light switches—with a disinfectant containing at least 70 % alcohol or a bleach solution (1 part bleach to 10 parts water).
Launder bedding, towels, and clothing used within the previous 48 hours in hot water (minimum 130 °F/54 °C) and dry on high heat.
Seal non‑washable items in plastic bags for two weeks; lice cannot survive beyond this period without a host.

Regular vacuuming, combined with thorough surface sanitation, deprives lice of potential habitats and supports overall eradication efforts.

Sealing Non-Washable Items

When head lice are detected, items that cannot be laundered become potential reservoirs for live insects and eggs. Protecting these objects by sealing them eliminates a common source of reinfestation.

Sealing creates an airtight barrier that deprives lice and nits of oxygen, causing mortality within a few days. The method applies to books, backpacks, electronics, pillows with non‑washable covers, and similar belongings.

Choose a sealable plastic bag or a vacuum‑sealed container large enough to accommodate the item without folding or crushing it.
Place the object inside, remove excess air, and close the seal tightly.
Store the sealed package at room temperature for a minimum of 72 hours; this period exceeds the survival time of both adult lice and nits.
After the exposure interval, open the package in a clean area, inspect the item, and discard any visible insects.

If the sealed item shows damage or cannot be isolated effectively, consider discarding it or consulting a pest‑control professional for specialized treatment. Label sealed packages clearly to avoid accidental opening during the waiting period.

Implementing airtight containment for non‑washable belongings complements chemical or manual lice removal and reduces the likelihood of recurrence.

Regular Checks for Re-infestation

After treatment, continuous monitoring prevents a second wave of infestation. Even when the initial outbreak appears resolved, nits can survive unnoticed and hatch later, reintroducing the problem.

Schedule examinations at regular intervals: three days after treatment, one week later, and then weekly for at least four weeks. During each session, examine the scalp, behind ears, and the nape of the neck with a fine-tooth comb under bright light. Record any live insects or viable eggs; immediate retreatment is required if they are discovered.

Use a clean comb for each inspection to avoid cross‑contamination.
Inspect each section of hair for at least two minutes, moving systematically from root to tip.
Document findings in a log, noting date, location, and presence of lice or nits.
If any live lice are seen, repeat the prescribed treatment according to the product’s instructions and continue the weekly checks.
Maintain the same routine for all household members, as asymptomatic carriers can trigger re‑infestation.

Educating Children on Lice Prevention

Avoiding Head-to-Head Contact

When lice are detected, preventing further transmission begins with eliminating direct head-to-head contact. This measure reduces the primary route through which nits and adult insects move between individuals.

Keep children’s hair separated during play, especially in close‑quarters activities such as wrestling, hugging, or sharing sleeping spaces.
Encourage the use of personal items—hats, helmets, scarves, hairbrushes, and headphones—without sharing them with others.
Arrange seating so that heads are not positioned side‑by‑side; for example, place chairs apart in classrooms or on buses.
Supervise group activities that involve physical contact, and intervene when children tilt their heads toward each other.

Consistently applying these practices curtails the spread of lice while other treatment steps address the existing infestation.

Not Sharing Personal Items

If lice are detected, immediate containment relies on limiting contact with personal belongings. The most effective barrier against spread is the strict avoidance of sharing any items that come into direct contact with hair or scalp.

Combs and brushes
Hair accessories (clips, bands, scarves)
Hats, caps, beanies
Headphones and earbuds
Pillowcases and bedding
Towels, washcloths, and hairdryers

Lice travel by crawling across fibers and can cling to eggs that remain attached to these objects. When an item moves from one person to another, both adult insects and viable nits are transferred, extending the infestation beyond the original host.

To enforce separation, assign each item a personal label, store it in a sealed container, and keep it away from communal areas. Disinfect shared surfaces with a lice‑specific spray or hot water (minimum 130 °F/54 °C) before reuse. Encourage all individuals in the household to retain their own supplies and to refuse borrowed objects until the outbreak is resolved.

By eliminating the exchange of personal items, the infestation’s lifecycle is disrupted, reducing the likelihood of re‑infestation and facilitating a faster return to a lice‑free environment.