Scabies Treatment
Topical permethrin 5% cream is the first-line treatment for uncomplicated scabies, applied from the neck down for 8-14 hours and washed off, with oral ivermectin (200 μg/kg, repeated in 2 weeks) as an equally effective alternative. 1, 2
First-Line Treatment Options
Permethrin 5% Cream (Preferred for Most Patients)
- Apply to all areas of the body from the neck down, including under fingernails and all body folds 1, 2
- Leave on for 8-14 hours before washing off 1, 2
- One application is generally curative in 96.9% of cases 3
- Permethrin is specifically recommended for infants, young children, and pregnant/lactating women due to its safety profile 1, 2
- Safe for children ≥2 months of age 2, 4
Oral Ivermectin (Alternative First-Line)
- Dose: 200 μg/kg, must be repeated in 2 weeks 1, 2
- Take with food to increase bioavailability and epidermal penetration 1, 2
- Contraindicated in children weighing <15 kg due to neurotoxicity risk 2
- Avoid in pregnant or lactating women due to limited safety data 2
- Single dose cure rate is only 62.4%, increasing to 92.8% with the second dose 3
Special Populations
Pregnant and Lactating Women
- Use permethrin 5% cream exclusively 2
- Avoid ivermectin due to insufficient safety data 2
- Permethrin is Pregnancy Category B with no evidence of fetal harm in animal studies 4
Infants and Young Children
- Permethrin 5% is safe for infants ≥2 months old 2, 4
- Do not use ivermectin in children <15 kg 2
- Avoid lindane entirely in children <10 years due to neurotoxicity risk 1, 2
Crusted (Norwegian) Scabies
- Requires aggressive combination therapy due to massive mite burden (thousands to millions of mites) 1, 2
- Regimen: 5% permethrin cream applied daily for 7 days, then twice weekly until cure 1, 2
- Plus oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2
- Single-application permethrin or single-dose ivermectin alone will fail 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 1, 2
- Treat contacts simultaneously even if asymptomatic to prevent reinfection 2
- Failure to treat contacts simultaneously is the most common cause of treatment failure 5
Environmental Decontamination
- Machine wash and dry bedding, clothing, and towels using hot cycles 1, 2
- Alternatively, dry clean or remove items from body contact for ≥72 hours 1, 2
- 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 1, 2
- In clinical trials, 75% of patients with pruritus at 2 weeks had resolution by 4 weeks 4
- Persistent symptoms do not indicate treatment failure during this period 1, 2
When to Retreat
- Consider retreatment only if symptoms persist beyond 2 weeks and live mites are observed 1, 2
- Reasons for persistent symptoms include treatment failure, reinfection from untreated contacts, or cross-reactivity with other household mites 1
Critical Pitfalls to Avoid
Application Errors
- Do not skip application under fingernails and to all body folds 1
- Ensure coverage from neck down to toes, including all creases 1, 2
- Trim fingernails short and apply medication underneath 6
Medication-Specific Errors
- Never skip the second dose of ivermectin at 2 weeks - essential for complete eradication 1, 5
- Avoid lindane in children <10 years, pregnant/lactating women, and those with extensive dermatitis due to neurotoxicity risk 1, 2
- Do not use lindane after bathing, as this increases absorption and toxicity 1, 5
Contact Management Failures
- Treating the patient alone without simultaneous treatment of contacts leads to reinfection 5
- Do not delay contact treatment - must be done simultaneously 2
Alternative Treatments (When First-Line Options Unavailable)
- Benzyl benzoate 25% demonstrated 87% cure rate vs. 27% for permethrin in a recent 2024 trial, suggesting potential permethrin resistance in some populations 7
- Lindane 1% is less effective and has significant neurotoxicity concerns 1, 2
- Sulfur 6% ointment applied for 3 consecutive nights is another option 5