What is the recommended treatment for scabies?

Scabies Treatment

Permethrin 5% cream is the first-line treatment for uncomplicated scabies, applied from the neck down for 8-14 hours, with oral ivermectin (200 μg/kg repeated in 2 weeks) as an equally effective alternative for most patients. 1, 2

First-Line Treatment Options

Topical Permethrin 5% Cream

• Apply to all areas of the body from the neck down, including under fingernails, between fingers and toes, and all body folds 1, 2
• Leave on for 8-14 hours before washing off 1, 2
• One application is generally curative in most cases 2
• Preferred for pregnant/lactating women, infants, and young children due to superior safety profile 1, 2

Oral Ivermectin

• Dose: 200 μg/kg, must be repeated in 2 weeks to address limited ovicidal activity 1, 2
• Take with food to increase bioavailability and epidermal penetration 1, 3
• Contraindicated in children weighing <15 kg due to neurotoxicity risk 2, 3
• Not recommended for pregnant/lactating women due to limited safety data 2, 3
• No dosage adjustment needed for renal impairment 1

The evidence shows comparable efficacy between these agents, though permethrin may provide slightly faster symptom resolution 4. A 2012 study found permethrin twice (1 week apart) achieved 92.5% cure at 2 weeks versus 85.9% for single-dose ivermectin 4.

Special Populations

Infants and Young Children

• Permethrin 5% is safe and effective in children ≥2 months old 2, 5
• Avoid ivermectin in children <15 kg 2, 3
• Never use lindane in children <10 years due to neurotoxicity risk 1, 2

Pregnant and Lactating Women

• Use permethrin exclusively - it is pregnancy category B with no evidence of fetal harm 2, 3, 5
• Avoid ivermectin due to insufficient safety data 2, 3
• Consider temporarily discontinuing nursing or withholding permethrin while breastfeeding given animal tumorigenicity data, though topical absorption is minimal 5

Crusted (Norwegian) Scabies

This severe form requires aggressive combination therapy, as single-agent treatment will fail. 1

• Topical 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
• This multiple-dose schedule addresses the massive mite burden (thousands to millions of mites) and ivermectin's limited ovicidal activity 1
• Single-application permethrin as used for ordinary scabies will fail 1
• Topical therapy alone is insufficient given thick crusts and mite burden 1

Contact and Environmental Management

Contact Tracing and Treatment

• Examine and treat ALL close personal, sexual, and household contacts within the preceding month, even if asymptomatic 1, 2, 3
• Failure to treat contacts simultaneously is the most common cause of treatment failure 3
• Treat all contacts at the same time to prevent reinfection 2

Environmental Decontamination

• Machine wash and dry all bedding, clothing, and towels using hot cycles 1, 2, 3
• Alternatively, dry clean items or remove from body contact for at least 72 hours 1, 3
• Fumigation of living areas is unnecessary 1, 3

Follow-Up and Persistent Symptoms

Expected Post-Treatment Course

• Pruritus, rash, and mild burning may persist for up to 2 weeks after successful treatment - this does NOT indicate treatment failure 1, 2, 5
• Approximately 75% of patients with persistent pruritus at 2 weeks will have resolution by 4 weeks 5
• Consider retreatment only if symptoms persist beyond 2 weeks AND live mites are observed 1, 2

Reasons for Treatment Failure

• Reinfection from untreated contacts or fomites 1
• Inadequate application of topical treatments (missing critical areas like under nails, body folds) 3
• Not repeating ivermectin dose at 2 weeks 1, 3
• Cross-reactivity with other household mites 1

Alternative Treatments (Less Preferred)

Lindane 1%

• Apply for 8 hours then wash off 3
• Avoid in children <10 years, pregnant/lactating women, and persons with extensive dermatitis due to neurotoxicity risk 1, 2, 3
• Never use after bathing, as this increases absorption and toxicity 1, 3
• Less effective than permethrin 1

Sulfur 6% Ointment

• Apply for 3 consecutive nights 3
• Alternative when other agents are contraindicated 1

Crotamiton 10%

• Significantly less effective than permethrin (60% cure at 4 weeks vs. 89% for permethrin in children) 6
• Requires application for 2 consecutive days, with cleansing bath 48 hours after last application 7

Critical Pitfalls to Avoid

• Not treating all close contacts simultaneously - leads to reinfection 1, 3
• Inadequate topical application - must include under nails, between all digits, and all body folds 3
• Forgetting to repeat ivermectin at 2 weeks - essential for complete eradication 1, 3
• Using lindane after bathing or in contraindicated populations - increases neurotoxicity risk 1, 3
• Expecting immediate symptom resolution - pruritus commonly persists 1-2 weeks post-treatment 1, 2, 5
• Using single-dose therapy for crusted scabies - requires aggressive combination approach 1