Treatment for Scabies
First-Line Treatment
Permethrin 5% cream is the gold standard first-line treatment for uncomplicated scabies, applied from the neck down (including scalp in infants and elderly) and washed off after 8-14 hours, with one application generally curative. 1, 2, 3
Application Details
- Apply thoroughly to all skin surfaces from the neck down, ensuring coverage under fingernails and to the edges of all body orifices 1
- In infants, young children, and geriatric patients, also treat the scalp, hairline, neck, temple, and forehead 2, 3
- Approximately 30 grams is sufficient for an average adult 3
- Leave on for 8-14 hours before washing off 1, 3
Alternative First-Line Option
- Oral ivermectin 200 μg/kg, repeated in 2 weeks, is an effective alternative first-line treatment 1, 2
- Must be taken with food to increase bioavailability and epidermal penetration 1, 2
- Contraindicated in children weighing less than 15 kg due to neurotoxicity risk 2
- No dosage adjustment needed for renal impairment 1
Special Populations
Pregnant and Lactating Women
Infants and Young Children
- Permethrin is preferred; avoid ivermectin in children <15 kg 2
- Do not use ivermectin in infants less than 2 months old 2
- Avoid lindane in children <10 years due to neurotoxicity risk 1, 2
Crusted (Norwegian) Scabies
- Requires aggressive combination therapy: topical 5% permethrin cream applied daily for 7 days, then twice weekly until cure, PLUS oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2
- Single-application permethrin or oral ivermectin alone will fail in crusted scabies 1
- This population harbors thousands to millions of mites and is far more contagious than typical scabies 1
Contact and Environmental Management
Contact Tracing and Treatment
- Examine and treat ALL persons with sexual, close personal, or household contact within the preceding month, even if asymptomatic 1, 2
- Failure to treat contacts simultaneously is the most common cause of treatment failure 1
Environmental Decontamination
- Machine wash and dry all bedding, clothing, and towels using hot cycles, or dry clean 1, 2
- Alternatively, remove items from body contact for at least 72 hours (or 2-3 weeks to be rigorous) 1, 4
- Fumigation of living areas is unnecessary 1, 2
Follow-Up and Persistent Symptoms
Expected Post-Treatment Course
- Rash and pruritus may persist for up to 2 weeks after successful treatment—this is NOT treatment failure 1, 2, 3
- Consider retreatment only after 2 weeks if symptoms persist AND live mites are observed 1, 2, 3
Treatment Failure Indicators
- Demonstrable living mites after 14 days indicate need for retreatment 3
- Common causes of failure: inadequate application, untreated contacts, failure to repeat ivermectin dose at 2 weeks 1
Alternative Treatments (When First-Line Options Unavailable)
- Benzyl benzoate 25% lotion (recent evidence suggests superior efficacy to permethrin in some settings) 5, 6
- Lindane 1% (apply for 8 hours)—avoid in children <10 years, pregnant/lactating women, and persons with extensive dermatitis due to neurotoxicity risk 1, 2
- Sulfur 6% ointment (apply for 3 consecutive nights) 1, 5
Critical Pitfalls to Avoid
- Not treating the scalp and face in infants and elderly patients 3
- Using lindane after bathing, which increases absorption and toxicity risk 1
- Failing to repeat ivermectin dose at 2 weeks 1
- Not treating all close contacts simultaneously 1
- Retreating patients unnecessarily for persistent pruritus within 2 weeks 1, 3
- Using single-dose therapy for crusted scabies 1