Treatment of Head Lice (Pediculosis Capitis)

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

First-Line Treatment Options

Apply to damp, shampooed hair (use non-conditioning shampoo) and towel-dried hair 1
Leave on for 10 minutes, then rinse off 1
Repeat application in 7-10 days (preferably day 9) to kill newly hatched nymphs 1
Has low mammalian toxicity and does not cause allergic reactions in patients with plant allergies 1
Leaves residue designed to kill nymphs emerging from eggs not killed by first application 1
Note: Conditioners and silicone-based additives in shampoos can impair permethrin adherence to hair shaft and reduce effectiveness 1

Apply to dry hair and rinse out after 10 minutes 1
Requires second treatment 7-10 days later as 20-30% of eggs remain viable after treatment 1
Contraindicated in patients with chrysanthemum allergies 1
Has extremely low mammalian toxicity 1

Indicated when resistance to permethrin or pyrethrins is documented or when first-line treatments fail despite correct use 1
For patients 24 months of age or older 1
Apply to DRY hair in amount sufficient to wet hair and scalp 2
Allow to air dry naturally (no heat source) and remain uncovered 2
Wash off after 8-12 hours 2, 1
Repeat in 7-9 days if lice are still present 2
Has high ovicidal activity 1
Caution: Highly flammable due to high alcohol content; risk of severe respiratory depression if ingested 1

Not recommended as first-line treatment due to safety concerns 1
Should only be used for patients who cannot tolerate or whose infestation has failed to respond to safer medications 1
Apply for no more than 4 minutes, repeat in 9-10 days 1
Has low ovicidal activity (30-50% of eggs not killed) 1
Contraindicated in neonates and should be used with extreme caution in children who weigh less than 50 kg 1
No longer recommended by the American Academy of Pediatrics due to risk of severe seizures 1
Banned in California 1

Oral ivermectin: Single dose of 200 mg/kg, repeated in 10 days 1
Should not be used for children who weigh less than 15 kg due to risk of crossing blood-brain barrier 1
Topical ivermectin 0.5% lotion has shown promising results but requires further testing 1, 3
Not currently FDA-approved for head lice treatment 1

Combination of permethrin 1% and trimethoprim/sulfamethoxazole has shown higher efficacy (92.5% success at 4 weeks) compared to either treatment alone 4
Consider for cases with multiple treatment failures or suspected resistance 4

Not necessary to prevent spreading infestation but recommended for aesthetic reasons 1
Use fine-toothed (nit) comb to remove dead lice and eggs 2
Vinegar or vinegar-based products applied to hair for 3 minutes before combing can help loosen nits 1

Never initiate treatment without clear diagnosis of head lice 1
Resistance to permethrin has been reported, but prevalence is unknown 1
Consider improper application as first cause of treatment failure before assuming resistance 1
Itching or mild burning of scalp after treatment is common and not a reason for re-treatment 1
Topical corticosteroids and oral antihistamines may help relieve post-treatment inflammation 1
Rinse all pediculicides over a sink (not in shower/bath) with warm (not hot) water to minimize absorption 1
Spraying or fogging a home with insecticides is not recommended 5