Treatment Options for Lice Infestation

Permethrin 1% cream rinse is the first-line treatment for head lice due to its effectiveness and safety profile. 1

First-Line Treatment: Permethrin 1%

Apply permethrin 1% cream rinse to damp hair that has been shampooed with a non-conditioning shampoo and towel dried 2, 1
Leave on for 10 minutes, then rinse off 2
Permethrin leaves a residue designed to kill nymphs emerging from eggs not killed with first application 2
A second treatment should be done in 7-10 days to kill newly hatched lice 2, 1
Permethrin has low mammalian toxicity and does not cause allergic reactions in patients with plant allergies 2
Resistance to permethrin has been reported, but prevalence is unknown 2, 1

Neurotoxic to lice with extremely low mammalian toxicity 2, 3
Apply to dry hair and rinse out after 10 minutes 2
Should be avoided in patients allergic to chrysanthemums 2
20-30% of eggs remain viable after treatment, requiring a second treatment in 7-10 days 2
Resistance has been reported 2

Indicated when resistance to permethrin or pyrethrins is documented or when first-line treatments fail despite correct use 2, 1
Apply to hair, leave to air dry, then wash off after 8-12 hours 2
Has high ovicidal activity but should be reapplied if live lice are seen in 7-10 days 2
Highly flammable due to high alcohol content - keep away from heat sources, electric hair dryers, and open flames 2, 4
Risk of severe respiratory depression if ingested 2, 5
Should not be used in children under 24 months 5

Should be left on for no more than 10 minutes with a second application in 7-10 days 2
Low ovicidal activity with worldwide resistance reported 2
Available only by prescription and should be used with caution due to risk of seizures in children 2
Not recommended as first-line treatment due to safety concerns 1, 5
Should only be used for patients who cannot tolerate or have failed to respond to safer medications 1

Oral ivermectin can be used as an alternative treatment at a single dose of 200 mg/kg, repeated in 10 days 1, 6
Should not be used for children who weigh less than 15 kg due to risk of crossing blood-brain barrier 1
Not currently FDA-approved for lice treatment 2, 7

Remove eggs (nits) after treatment for aesthetic reasons using a fine-toothed comb 2, 3
Vinegar or vinegar-based products applied to hair for 3 minutes before combing help loosen nits 2, 1
Clean hair care items and bedding belonging to infested person 2, 8
All household members should be checked, and only those with live lice or eggs within 1 cm of the scalp should be treated 2, 8
Treat family members who share a bed with the infested person 2, 8

Never initiate treatment without clear diagnosis of head lice 2, 8
Consider improper application first as cause of treatment failure before assuming resistance 2, 8
Conditioners and silicone-based additives in shampoos can impair permethrin adherence to hair shafts and reduce effectiveness 2
For persistent cases, consider misdiagnosis, noncompliance with treatment protocol, reinfestation, lack of ovicidal properties, or resistance 2
Avoid unnecessary treatment of all family members without evidence of infestation 8

Children can return to school after proper treatment and should not miss valuable school time because of head lice 2
Topical corticosteroids and oral antihistamines may help relieve post-treatment inflammation 2, 1
Malathion should be used only under direct adult supervision due to flammability concerns 4
Environmental cleaning should include washing bedding and clothing in hot water (above 54°C/130°F) and drying on hot cycle for at least 20 minutes 3