Scabies Treatment
Permethrin 5% cream applied from the neck down for 8-14 hours is the first-line treatment for uncomplicated scabies, with oral ivermectin 200 μg/kg (repeated in 2 weeks) as an equally effective first-line alternative. 1, 2
First-Line Treatment Options
Topical Permethrin 5% Cream
- Apply to all areas of the body from the neck down and wash off after 8-14 hours 1, 2, 3
- This is the preferred treatment for infants, young children, and pregnant/lactating women 1, 2, 3
- Safe for use in pediatric patients two months of age and older 4
- However, recent high-quality evidence from 2024 shows permethrin may have reduced efficacy, with only a 27% cure rate compared to historical expectations 5
Oral Ivermectin
- Dose: 200 μg/kg body weight, repeated after 2 weeks 1, 2
- Must be taken with food to increase bioavailability and epidermal penetration 1, 2
- No dosage adjustments needed for renal impairment 1
- Particularly useful for institutional outbreaks, immunocompromised patients, and when topical therapy adherence is poor 1, 2
Alternative Treatment Options (When First-Line Fails or Is Unavailable)
Benzyl benzoate 25%: Demonstrated 87% cure rate in a 2024 head-to-head trial vs. permethrin's 27% 5
Lindane 1%: Apply thinly from neck down, wash off after 8 hours 2
Sulfur 6% ointment: Apply nightly for 3 consecutive nights 1, 2
Crotamiton 10%: Apply nightly for 2 consecutive nights, wash off 24 hours after second application 2, 6
Crusted (Norwegian) Scabies - Requires Aggressive Combination Therapy
This severe form requires both topical and oral treatment simultaneously: 1, 2
- Permethrin 5% 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 will fail in crusted scabies 1
- Topical therapy alone is insufficient given the massive mite burden (thousands to millions of mites) 1
- These patients should be isolated, and all contacts must be treated 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, 3
- Treat contacts simultaneously to prevent reinfection 1, 2
- For institutional outbreaks, treat the entire at-risk population 2
Environmental Decontamination
- Machine wash and dry bedding/clothing using hot cycle, OR dry clean, OR remove from body contact for at least 72 hours 1, 2, 3
- Fumigation of living areas is unnecessary 1, 2
- Keep fingernails closely trimmed to reduce injury from scratching 2
Follow-Up and Managing Persistent Symptoms
- Pruritus and rash may persist for up to 2 weeks after successful treatment - this is normal 1, 2, 4
- In clinical trials, approximately 75% of patients with persistent pruritus at 2 weeks had resolution by 4 weeks 4
- Evaluate at 2 weeks post-treatment; consider retreatment if symptoms persist beyond 2 weeks OR live mites are observed 1, 2
Reasons for Treatment Failure
- Failure to treat all close contacts simultaneously 1, 2
- Inadequate application of topical treatments 1, 2
- Reinfection from untreated contacts or fomites 1, 2
- Not repeating ivermectin dose after 2 weeks 1
- Possible medication resistance (particularly with permethrin) 5
Critical Pitfalls to Avoid
- Do not use lindane after bathing or in children <10 years, pregnant/lactating women, or persons with extensive dermatitis 1, 2
- Do not skip the second dose of ivermectin at 2 weeks 1, 2
- Do not expect immediate symptom resolution - allow up to 2 weeks for pruritus to resolve 1, 2, 4
- Do not use single-application permethrin for crusted scabies 1
- Do not forget to treat all household and close contacts simultaneously 1, 2
Special Population Considerations
Pregnant/Lactating Women
Infants and Young Children
- Permethrin 5% cream is safe for infants ≥2 months of age 1, 4
- Avoid lindane in children <10 years 1, 2