What are the recommended treatments for a patient with scabies?

Scabies Treatment

First-Line Treatment Recommendation

Permethrin 5% cream is the first-line treatment for uncomplicated scabies, applied to all areas of the body from the neck down and washed off after 8-14 hours. 1, 2 This recommendation is based on CDC guidelines and represents the gold standard therapy with the best safety profile, particularly for vulnerable populations including infants over 2 months, children, and pregnant or lactating women. 1, 2, 3

Primary Treatment Options

Topical Permethrin 5% Cream

• Application technique: Apply to entire body from neck down, including under fingernails, in skin folds, and all creases 1, 2
• Duration: Leave on for 8-14 hours before washing off 4, 1
• Advantages: Safest option with lowest toxicity risk, even with inappropriate use 4
• Cost consideration: More expensive than lindane but superior safety profile justifies the cost 4

Oral Ivermectin

• Dosing: 200 μg/kg body weight, taken with food to increase bioavailability 1, 2
• Repeat dose: Second dose required after 2 weeks to address limited ovicidal activity 1, 2
• Preferred scenarios: Institutional outbreaks, bedridden patients, treatment failures with topical therapy 5
• No renal adjustment needed 1

Alternative Treatment Options (When First-Line Unavailable or Fails)

Lindane 1%

• Application: Apply thinly from neck down, wash off after 8 hours 4, 2
• Critical contraindications:
  • Children <10 years of age 1, 2
  • Pregnant or lactating women 4, 1
  • Persons with extensive dermatitis 4, 2
• Major safety concern: Risk of seizures and neurotoxicity, especially if applied after bathing (increases absorption) 4, 1
• Resistance reported in some geographic areas 4

Crotamiton 10%

• Application: Apply nightly for 2 consecutive nights, wash off 24 hours after second application 4, 6
• Less effective than permethrin or ivermectin 4

Sulfur 6% Ointment

• Application: Apply nightly for 3 nights, washing off previous applications before reapplying 2
• Use case: Alternative when other options unavailable 1

Special Population Considerations

Pregnant and Lactating Women

• Use permethrin 5% cream exclusively - it is the safest option with minimal systemic absorption 1, 2, 3
• Avoid lindane completely due to neurotoxicity risk 4, 1

Infants and Young Children

• Permethrin 5% is safe for infants ≥2 months of age 1, 3
• Include scalp and face in treatment application for young children 5
• Never use lindane in children <10 years 1, 2

Crusted (Norwegian) Scabies

This requires aggressive combination therapy due to massive mite burden (thousands to millions of mites). 1

• Combination regimen:
  • 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
• Critical pitfall: Single-application permethrin as used for ordinary scabies will fail 1
• Never use lindane in this population (often immunocompromised/debilitated) 1

Essential Management Beyond Medication

Contact Treatment

• Treat all close contacts simultaneously within the preceding month, including sexual partners, household members, and close personal contacts 1, 2
• Failure to treat contacts simultaneously is a leading cause of treatment failure and reinfection 1, 2

Environmental Decontamination

• Bedding and clothing: Machine wash and dry using hot cycle, or dry-clean 4, 1, 2
• Alternative: Remove items from body contact for at least 72 hours 4, 1
• Fumigation is unnecessary 4, 1
• Trim fingernails short to reduce scratching injury and mite harboring 2, 5

Follow-Up and Treatment Failure Management

Expected Post-Treatment Course

• Pruritus may persist for up to 2 weeks after successful treatment due to hypersensitivity reaction to dead mites 1, 2, 3
• Approximately 75% of patients with persistent itching at 2 weeks will have resolution by 4 weeks 3

When to Retreat

• Consider retreatment after 2 weeks if symptoms persist or live mites are observed 1, 2
• Some experts recommend retreatment at 1 week for symptomatic patients 4

Common Causes of Treatment Failure

• Inadequate application of topical treatment (missing areas like finger webs, under nails, skin folds) 1, 2
• Failure to treat all close contacts simultaneously 1, 2
• Reinfection from untreated contacts or contaminated fomites 1, 2
• Not repeating ivermectin dose at 2 weeks 1
• Using lindane after bathing (increases absorption and toxicity risk) 1, 2
• Medication resistance (rare but reported with lindane) 4, 2

Critical Pitfalls to Avoid

• Never apply lindane after bathing - this dramatically increases systemic absorption and seizure risk 4, 2
• Do not use lindane in contraindicated populations despite lower cost 4, 1
• Do not expect immediate symptom resolution - itching can persist 2 weeks after successful treatment 1, 3
• Do not skip the second ivermectin dose at 2 weeks - single dose has lower cure rates 1, 7
• Do not forget to treat the scalp and face in young children and immunocompromised patients 5
• Avoid eye contact with all topical treatments; flush immediately if contact occurs 8, 3