Head Lice Treatment

Lice are confirmed by finding live lice or viable nits (eggs) attached to the hair shaft within a quarter inch of the scalp. Itching alone isn't diagnostic — a careful examination with a fine-tooth comb under good lighting is the most reliable method.

OTC permethrin and pyrethrins work well in most cases. Prescription options — like spinosad, topical ivermectin, or benzyl alcohol — are recommended when OTC treatments have failed or when resistance is suspected, which is increasingly common in some regions.

Lice cannot survive more than 24–48 hours off a human host and cannot live on pets. Washing bedding and recently used items in hot water is sensible, but extensive environmental treatment is generally unnecessary and not supported by evidence.

Avoid head-to-head contact and sharing hair accessories during active outbreaks. Completing the full treatment course — including a repeat application — is the most important step. Check household contacts and treat anyone with confirmed infestation simultaneously.

OTC permethrin and pyrethrins may cause mild scalp irritation. Prescription topical ivermectin and spinosad are generally well tolerated. None should be used near the eyes. Oral ivermectin, used off-label, carries a broader systemic side effect profile. Head Lice visit What to expect from a Head Lice visit