Lice Treatment Schedule Calculator
Lice retreat dates and comb checks from find date and product.
What it does
Head lice clear on schedules, not single doses: non-ovicidal products need day 9 retreats while comb checks every 2 to 3 days catch hatchlings across the 21-day cycle. Home suffocation remedies lack proof.
The tool above takes the find date with the product. It returns the retreat date with the first comb checks and the 3-week span.
The default Oct 5 permethrin retreats Wed Oct 14 with checks Oct 7, 9, and 12. Malathion from the same date retreats Oct 12.
Timing follows CDC treatment pages with the AAP 2022 clinical report behind them. Both agree on day 9 permethrin retreats used here.
How to use
- Enter the find date.
- Pick the treatment product.
- Read the retreat date first.
- Read the first checks beside it.
- Comb every 2 to 3 days after.
- Call out at failure rules.
Formula
- found
- Date live lice were found.
- gap
- Retreat gap by product label.
- checks
- First three comb check dates.
Day 0 counts the find date with whole calendar days after. Spinosad returns single dose unless live lice appear. Age floors apply: permethrin 2 months+, pyrethrins 2 years+, spinosad and ivermectin 6 months+, malathion 6 years+.
Worked example
Example: permethrin from Oct 5
Defaults: found Oct 5 2026, permethrin.
- Found: Oct 5 2026, permethrin day 0.
- Retreat: day 9 = Oct 14.
- Checks: +2, +4, +7 days = Oct 7, 9, 12.
- Then every 2 to 3 days for 3 weeks.
- Stop rules: no dead lice in 12 hr, call clinician.
- Weekday: Oct 14 2026 is Wednesday.
- Tool shows Wed Oct 14 2026, Oct 7, Oct 9, Oct 12.
Reference table
| Product | Retreat | Note |
|---|---|---|
| Permethrin 1% | Day 9 | Kills lice, not eggs |
| Pyrethrins | Day 9 | Kills lice, not eggs |
| Malathion | Day 7 to 9 | If live lice seen |
| Spinosad | Single | Retreat day 7 if live |
Limits
- Guidance only; clinicians rule failures.
- Age floors per product label.
- Resistance varies by area.
- Itch alone never retreats.
Common mistakes
- Skipping the second dose.
- Mixing products unasked.
- Conditioning before treatment.
- Fumigating houses and cars.
- Excluding kids for nits.
Try it yourself
Quick checks. Answers sit tucked under each question.
Permethrin found Oct 1?
Found Oct 1 + 9 = Sat Oct 10 2026.
Malathion found Oct 5?
Malathion gap 7: Oct 5 + 7 = Mon Oct 12 2026.
Spinosad found Oct 5?
Single dose unless live lice seen; then day 7.
Questions
What is the lice schedule?
Day 0 treatment, comb checks every 2 to 3 days for 2 to 3 weeks, retreat per product day.
When is the second dose?
Day 9 for permethrin and pyrethrins; day 7 to 9 malathion if live lice; spinosad usually single.
How are topicals applied?
Over a sink with warm water, no conditioner before, no rewash 1 to 2 days after.
Do home suffocation remedies work?
No. Mayonnaise, oils, and essential oils lack proof; gasoline and foggers are dangerous.
Must schools exclude for nits?
No. No-nit exclusion is not advised; return after starting treatment.
Does itching mean failure?
Itch lingers after cure. Retreat only for live lice past 3 weeks or repeated product failure.