What should I do if a lice treatment does not work? - briefly
Repeat the treatment using a product with a different active ingredient and follow the instructions carefully, while washing clothing, bedding, and personal items in hot water. If lice remain, seek advice from a healthcare professional for prescription‑strength options.
What should I do if a lice treatment does not work? - in detail
If an initial lice remedy proves ineffective, confirm that the product was applied exactly as the label directs: correct dosage, thorough coverage of hair and scalp, and sufficient contact time. Incomplete application is a common cause of persistence.
Next, assess whether the lice may be resistant to the active ingredient. Many over‑the‑counter options contain pyrethrins or permethrin; resistance to these chemicals is documented. Switching to a formula with a different mode of action—such as dimethicone, ivermectin, or a prescription‑only preparation—can overcome resistance.
Mechanical removal remains essential regardless of chemical treatment. Use a fine‑toothed nit comb on wet, conditioned hair. Comb from the scalp outward, repeating every 2–3 days for at least two weeks. Remove each captured egg or nymph and discard it promptly.
Environmental measures reduce reinfestation risk. Wash all washable items (clothing, bedding, towels) in hot water (≥130 °F/54 °C) and dry on high heat. Seal non‑washable items in sealed plastic bags for two weeks. Vacuum carpets, upholstery, and car seats; discard the vacuum bag or empty the canister immediately.
If the infestation persists after a second, correctly performed treatment, consider a combination approach: apply a second‑line chemical product followed by diligent combing for several days. Ensure a minimum interval of 7–10 days between different chemical treatments to avoid scalp irritation.
Consult a healthcare professional when:
- The scalp shows signs of severe irritation or allergic reaction.
- Infestation continues after two distinct treatment cycles.
- Young children, pregnant individuals, or those with compromised skin barriers are affected.
Professional options include prescription oral ivermectin, benzyl alcohol lotion, or supervised nit removal in a clinical setting. These interventions provide higher efficacy and safety monitoring.