How to Apply Permethrin for Scabies and Lice
For Head Lice (1% Permethrin Cream Rinse)
Apply 1% permethrin cream rinse to damp, towel-dried hair after shampooing with a non-conditioning shampoo, leave on for 10 minutes, then rinse thoroughly with warm water over a sink. 1, 2
Step-by-Step Application Instructions:
First, wash hair with a non-conditioning shampoo (conditioning products can interfere with permethrin's ability to adhere to the hair shaft) and towel dry until damp 1
Apply the 1% permethrin cream rinse thoroughly to cover all hair and scalp areas 1, 2
Leave the product on for exactly 10 minutes (not longer or shorter) 1, 2
Rinse over a sink with warm water (not hot water, as this increases absorption through vasodilation; avoid rinsing in shower or bath to limit unnecessary skin exposure) 1, 2
Repeat the application in 7-10 days to kill newly hatched nymphs, as permethrin has only 70-80% ovicidal activity and cannot kill all eggs with the first treatment 1, 2
Special Considerations for Head Lice:
In infants and elderly patients, apply to the scalp, hairline, neck, temple, and forehead as these areas are more commonly infested in these age groups 1, 3
Post-treatment itching is normal and not a sign of treatment failure—it can persist for many days after lice are killed due to inflammatory response 1, 2
Only retreat if live lice are seen 7-10 days after treatment; persistent itching alone is not an indication for retreatment 1, 2
For Scabies (5% Permethrin Cream)
Thoroughly massage 5% permethrin cream into the skin from head to soles of feet, leave on for 8-14 hours, then wash off completely in a shower or bath. 3
Step-by-Step Application Instructions:
Apply cream to the entire body from head to toe, including under fingernails and toenails 3
In adults, the scalp is rarely infested, but in infants and elderly patients, apply to the scalp, temple, forehead, and hairline 3
Use approximately 30 grams for an average adult (one full tube is typically sufficient) 3
Leave the cream on for 8-14 hours (overnight application is most practical) 3
Wash off thoroughly with a shower or bath after the contact time 3
One application is generally curative—retreatment is only necessary if living mites are demonstrated after 14 days 3
Special Considerations for Scabies:
Persistent itching after treatment is common and rarely indicates treatment failure; it is not an indication for retreatment unless live mites are found 3
Safe for use in infants as young as 2 months of age 1
Permethrin is recommended for pregnant women and nursing mothers as it has low mammalian toxicity and minimal percutaneous absorption 4, 5
Environmental Measures (Critical for Both Conditions)
Wash all clothing, bedding, and linens in hot water and dry on hot cycle on the same day as treatment 2, 4, 6
Items that cannot be washed should be removed from body contact for at least 72 hours (lice and mites cannot survive off the human body for more than 2-3 days) 4
Wash hair care items (combs, brushes) in hot water 2
Fumigation of living areas is not necessary 4
Common Pitfalls to Avoid
Do not use conditioning shampoo before applying permethrin for lice—it prevents proper adherence 1
Do not rinse with hot water—warm water minimizes absorption 1, 2
Do not retreat based on itching alone—post-treatment pruritus is an inflammatory response, not treatment failure 1, 2, 3
Do not assume treatment failure before considering improper application—most "resistance" is actually due to incorrect use 2
Do not skip the second application for head lice—it is mandatory due to incomplete egg kill 1, 2