Scabies Management
First-Line Treatment Recommendation
Permethrin 5% cream is the recommended first-line treatment for uncomplicated scabies, applied to all areas of the body from the neck down and washed off after 8-14 hours, with oral ivermectin (200 μg/kg) as an equally effective alternative. 1, 2
Standard Treatment Protocol
Topical Permethrin 5% Cream
- Apply to entire body surface from neck down, including all skin folds, creases, under fingernails, and between fingers and toes 1, 2
- Leave on skin for 8-14 hours before washing off 1, 2
- Repeat application after 7-10 days (second treatment is essential) 1
- Note: Recent evidence suggests permethrin may have reduced efficacy in some populations, with cure rates as low as 27% in one 2024 trial, compared to 87% for benzyl benzoate 3
Oral Ivermectin
- Dose: 200 μg/kg body weight 1, 2
- Must be taken with food to increase bioavailability and epidermal penetration 2
- Mandatory second dose after 2 weeks 1, 2
- No renal dose adjustment needed 2
- Particularly useful for institutional outbreaks and mass treatment 4
Special Population Considerations
Pregnant and Lactating Women
- Permethrin 5% cream is the preferred treatment 1, 2
- Ivermectin can be administered during lactation 4
Pediatric Patients
- Permethrin is safe and effective in children ≥2 months of age 1, 2, 5
- Avoid lindane in children <10 years due to neurotoxicity risk 1, 2
- New evidence suggests ivermectin is safe in children >15 kg 4
Immunocompromised Patients
- Higher risk for crusted (Norwegian) scabies requiring aggressive treatment 1, 2
- Closer monitoring necessary due to increased treatment failure risk 2
Crusted (Norwegian) Scabies Protocol
Combination therapy is mandatory: 1, 2
- Permethrin 5% 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
Alternative Treatment Options
When First-Line Fails or Is Unavailable
- Benzyl benzoate 25% shows superior efficacy (87% cure rate vs 27% for permethrin in recent trial) 3
- Sulfur 6% ointment: apply nightly for 3 consecutive nights, washing off previous applications before reapplying 1
- Lindane 1%: apply thinly from neck down, wash off after 8 hours 1, 2
Lindane Contraindications (Absolute)
- Children <10 years 1, 2
- Pregnant or lactating women 1, 2
- Persons with extensive dermatitis (increased absorption risk leading to seizures) 1, 2
- Never apply after bathing (increases absorption) 1, 2
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 all contacts simultaneously, even if asymptomatic 1
- For institutional outbreaks, treat entire at-risk population and consult expert 1
Environmental Decontamination
- Machine wash and dry bedding/clothing using hot cycle 1, 2
- Alternatively: dry clean or remove from body contact for ≥72 hours 1, 2
- Fumigation of living areas is unnecessary 1, 2
- Trim fingernails closely to reduce scratching injury 1
Follow-Up and Treatment Failure Management
Expected Post-Treatment Course
- Pruritus and rash may persist for up to 2 weeks after successful treatment 1, 2
- Approximately 75% of patients with persistent pruritus at 2 weeks will resolve by 4 weeks 5
Indications for Retreatment (After 2 Weeks)
Common Causes of Treatment Failure
- Resistance to medication (particularly permethrin) 1, 3
- Faulty application of topical treatments 1, 2
- Reinfection from untreated contacts or fomites 1, 2
- Cross-reactivity with other household mites 1, 2
Critical Pitfalls to Avoid
- Failure to treat all close contacts simultaneously 1, 2
- Inadequate application (must cover entire body from neck down) 1, 2
- Not repeating treatment dose (second application at 7-14 days is mandatory) 1, 2
- Using lindane in contraindicated populations or after bathing 1, 2
- Expecting immediate symptom resolution 1, 2
- Discontinuing treatment due to persistent pruritus before 2-week mark 1, 2, 5