What to do if lice persist? - briefly
If lice survive the first treatment, apply a second‑generation pediculicide and repeat the application after 7–10 days according to the product instructions. Continued infestation requires medical evaluation and thorough cleaning of personal items and living areas.
What to do if lice persist? - in detail
Persistent head‑lice infestations require systematic action. First, verify that live lice or viable nits remain after the initial treatment; visual inspection under bright light or a magnifying lens confirms the presence of moving insects or eggs within three millimetres of the scalp.
If lice are still detected, follow these steps:
- Repeat the primary treatment – most over‑the‑counter products specify a second application 7–10 days after the first dose. Apply exactly as directed, ensuring thorough coverage of hair and scalp.
- Switch to a different active ingredient – resistance to pyrethrins or permethrin is common. Options include:
- 1% spinosad lotion
- 0.5% ivermectin oral tablets (prescription)
- Malathion 0.5% lotion
- Combine chemical treatment with mechanical removal – use a fine‑toothed nit comb on wet, conditioned hair. Comb from scalp to ends, cleaning the comb after each pass. Perform this process daily for at least one week.
- Treat the environment – wash all bedding, clothing, and towels used within the previous 48 hours in hot water (≥ 60 °C) and tumble‑dry on high heat. Items that cannot be laundered should be sealed in a plastic bag for two weeks. Vacuum carpets, upholstered furniture, and car seats; discard used combs or brushes.
- Monitor close contacts – examine household members, classmates, and anyone with prolonged head‑to‑head contact. Treat any additional cases simultaneously to prevent re‑infestation.
- Seek professional medical advice – if two treatment cycles fail, consult a healthcare provider. Prescription‑strength options, such as oral ivermectin or benzyl alcohol lotion, may be recommended.
- Consider alternative therapies with caution – essential‑oil preparations (e.g., tea‑tree oil, neem oil) lack consistent efficacy data and may cause scalp irritation. Use only under medical supervision.
After completing the chosen regimen, perform weekly scalp checks for four weeks. Absence of live lice and empty nits indicates successful eradication. Persistent detection beyond this period warrants specialist evaluation for possible resistance or misdiagnosis.