What is the recommended treatment for head lice in children?

Treatment of Head Lice in Children

Permethrin 1% cream rinse is the recommended first-line treatment for head lice in children, applied to damp, towel-dried hair for exactly 10 minutes, then rinsed off, with a mandatory second application 7-10 days later. 1, 2

First-Line Treatment: Permethrin 1%

Application Protocol:

• Shampoo hair first with a non-conditioning shampoo (conditioning products prevent proper adherence and cause treatment failure) 2
• Towel dry hair until damp, not soaking wet 1, 2
• Apply permethrin 1% cream rinse thoroughly to all hair, paying special attention to the scalp, hairline, neck, temples, and behind ears 2
• Leave on for exactly 10 minutes—not longer or shorter 2
• Rinse over a sink with warm water (not hot) to minimize systemic absorption 1, 2
• Mandatory second application on day 7-10 because permethrin has only 70-80% ovicidal activity, meaning 20-30% of eggs survive the first treatment 1, 2

Safety Profile:

• Permethrin has extremely low mammalian toxicity and does not cause allergic reactions in patients with plant allergies 3
• Safe for children 2 years and older 4

Alternative First-Line Option: Pyrethrins with Piperonyl Butoxide

• Apply to dry hair (unlike permethrin which goes on damp hair), leave for 10 minutes, then rinse 3
• Also requires second application in 7-10 days due to 20-30% egg survival 3
• Avoid in patients allergic to chrysanthemums 3
• Has extremely low mammalian toxicity 3

Second-Line Treatment: Malathion 0.5%

Use malathion only when:

• Documented resistance to permethrin exists 1
• First-line treatments have failed despite correct application 1
• Multiple treatment failures have occurred 5

Application Protocol:

• Apply to dry hair, allow to air dry naturally, then wash off after 8-12 hours 3
• Has the highest ovicidal activity of all treatments (approximately 98%), so often a single application is adequate 1, 6
• Reapply in 7-9 days only if live lice are still visible 3

Critical Safety Warnings:

• Contains 78% isopropyl alcohol making it highly flammable 3, 1
• Do NOT use hair dryers, curling irons, or flat irons while hair is wet 3
• Do NOT smoke near a child receiving treatment 3
• Contraindicated in children younger than 24 months 3
• Not approved for children under 6 years in some formulations 3
• Theoretical risk of respiratory depression if ingested (cholinesterase inhibitor), though no cases reported 3

Third-Line Treatment: Spinosad 0.9%

• Apply to dry hair for 10 minutes, then rinse thoroughly 1
• Achieves high cure rates with a single 10-minute application 1
• Approved for children 6 months and older 3

Benzyl Alcohol 5%

• Kills lice by asphyxiation, not neurotoxicity 3
• Apply for 10 minutes, repeat in 7 days 3
• Not ovicidal, so requires multiple applications 3
• More than 75% of subjects were lice-free 14 days after treatment 3
• Approved for children older than 6 months 3

Treatments to AVOID or Use with Extreme Caution

Lindane 1%:

• Do NOT use as first-line treatment due to severe safety concerns 1
• Only use when all other treatments have failed and patient can tolerate it 3, 1
• Has caused seizures in children 3
• Low ovicidal activity (only kills 30-50% of eggs) 3, 1
• Widespread resistance reported worldwide 3
• Contraindicated in neonates 3

Oral Ivermectin:

• Not FDA-approved for head lice 3, 1
• Do NOT use in children weighing less than 15 kg due to risk of blood-brain barrier penetration 1
• If used: 200 mcg/kg single dose, repeated in 10 days 1

Combination Therapy (Permethrin + Trimethoprim-Sulfamethoxazole):

• One study showed 92.5% success rate at 4 weeks versus 72% for permethrin alone 5
• However, this is not FDA-approved and should be reserved for multiple treatment failures or suspected resistance 3, 5

Critical Management Points

Who to Treat:

• Examine all household members with a magnifying glass in bright light 4
• Only treat those with live lice OR nits within 1 cm of the scalp 3, 1
• Treat family members who share a bed with the infected person 3, 2

Nit Removal:

• Not necessary to prevent spread, but recommended to decrease diagnostic confusion 3
• Use a fine-tooth nit comb on slightly damp hair 4
• Apply vinegar or vinegar-based products for 3 minutes before combing to loosen nits 3, 1
• Part hair into 1-2 inch sections and comb from scalp outward 4

Environmental Decontamination:

• Wash all clothing, bedding, and linens in hot water and dry on hot cycle on the same day as treatment 2
• Wash hair care items (combs, brushes) in hot water 2
• Remove items that cannot be washed from body contact for at least 72 hours (lice cannot survive off the human body more than 2-3 days) 2
• Fumigation is NOT necessary 2

Common Pitfalls to Avoid

Post-Treatment Itching is NOT Treatment Failure:

• Itching commonly persists for many days after successful treatment due to inflammatory response 1, 2
• Do NOT retreat based on itching alone—only retreat if live lice are seen 7-10 days after treatment 2
• Topical corticosteroids and oral antihistamines can relieve post-treatment inflammation 3, 1

Most "Resistance" is Actually Improper Application:

• Before assuming resistance, consider: misdiagnosis, noncompliance with treatment protocol, reinfestation, or improper application technique 3, 1
• Using conditioning shampoo before permethrin prevents proper adherence and causes failure 2
• Not doing the mandatory second application is a common cause of "treatment failure" 2

School Attendance:

• A child with head lice has likely had the infestation for a month or more by the time discovered and poses little risk to others 3
• The child should stay in class but be discouraged from close, direct head-to-head contact 3
• "No-nit" school policies are detrimental and cause unnecessary lost classroom time 6