What is the recommended treatment for a patient with scabies?

Scabies Management

First-Line Treatment Recommendation

Permethrin 5% cream applied to all areas of the body from the neck down and washed off after 8-14 hours is the recommended first-line treatment for uncomplicated scabies. 1, 2, 3

Oral ivermectin 200 μg/kg (taken with food, repeated in 2 weeks) is equally recommended as a first-line option, particularly useful for patients with poor adherence to topical therapy or in outbreak settings. 1, 2

Treatment Algorithm by Clinical Scenario

Uncomplicated Scabies in Immunocompetent Adults

• Apply permethrin 5% cream from neck down to entire body surface, leave on for 8-14 hours, then wash off 1, 2, 3
• Alternative: Oral ivermectin 200 μg/kg with food, repeat dose after exactly 2 weeks 1, 2
• The ivermectin must be taken with food to increase bioavailability and epidermal penetration 2

Special Populations Requiring Modified Approach

Pregnant or Lactating Women:

• Use permethrin 5% cream exclusively - this is the only recommended agent for this population 1, 3
• Avoid lindane completely due to neurotoxicity risk 1, 2
• Avoid oral ivermectin (insufficient safety data) 1

Infants and Children:

• Permethrin 5% is safe for children ≥2 months of age 3
• Never use lindane in children <10 years due to risk of seizures and neurotoxicity 1, 2
• Infants <2 months: safety not established; consider sulfur 6% ointment as alternative 1

Immunocompromised Patients:

• Higher risk for crusted (Norwegian) scabies requiring more aggressive treatment 1
• Closer monitoring necessary as treatment failure rates are higher 2
• Consider combination therapy preemptively if extensive disease 2

Crusted (Norwegian) Scabies - Aggressive Combination Required

This severe form requires combination therapy; single-agent treatment will fail. 2

• Topical: Permethrin 5% cream applied daily for 7 consecutive days, then twice weekly until cure 1, 2
• PLUS Oral: Ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2
• The multiple-dose ivermectin schedule addresses the massive mite burden (thousands to millions of mites) and ivermectin's limited ovicidal activity 2
• Patient isolation is mandatory with treatment of all contacts 2

Alternative Treatment Options (Second-Line)

When permethrin fails or is unavailable:

• Lindane 1%: Apply thinly from neck down, wash off after 8 hours 4, 1, 2

  • Critical contraindications: Children <10 years, pregnant/lactating women, extensive dermatitis, never use after bathing (increases absorption and seizure risk) 4, 1, 2
  • Resistance reported in some U.S. regions 4

• Sulfur 6% ointment: Apply nightly for 3 consecutive nights, washing off previous applications before reapplying 1

  • One study showed 10% sulfur ointment significantly more effective than permethrin (p<0.001), though this contradicts guideline hierarchy 5

• Crotamiton 10%: Apply to entire body nightly for 2 consecutive nights, wash off 24 hours after second application 4, 6

• Benzyl benzoate 25%: 87% cure rate but causes burning sensation in 43% of patients 1

Environmental Decontamination - Essential to Prevent Reinfection

• Machine wash and dry all bedding, clothing, and towels using hot cycle 4, 1, 2, 3
• Alternative: Dry-clean or remove items from body contact for minimum 72 hours (mite survival limited to 48 hours at room temperature) 4, 1, 2, 7
• Fumigation of living areas is completely unnecessary 4, 1, 2
• Trim fingernails short and apply medication under nails (mites commonly harbor there) 1, 6

Contact Management - Critical for Treatment Success

• Examine and treat ALL persons with sexual, close personal, or household contact within the preceding month 1, 2, 3
• Treat contacts simultaneously with the index patient, even if asymptomatic 1, 3
• For institutional outbreaks (nursing homes, refugee centers): treat entire at-risk population and consult infectious disease expert 1, 7

Follow-Up and Expected Timeline

• Pruritus commonly persists for up to 2 weeks after successful treatment - this is normal and does not indicate treatment failure 1, 2, 8
• In clinical trials, 75% of patients with persistent itching at 2 weeks had complete resolution by 4 weeks 8
• Evaluate at 2 weeks post-treatment: Consider retreatment only if live mites observed, new lesions appear, or symptoms persist beyond 2 weeks 1, 2
• Some experts recommend empiric retreatment at 1 week for symptomatic patients, though others wait for evidence of live mites 4, 2

Critical Pitfalls to Avoid

These errors account for most treatment failures:

• Failure to treat all close contacts simultaneously - leads to immediate reinfection 1, 2
• Inadequate topical application - must cover entire body from neck down, including between fingers/toes, under nails, in body folds 1, 2
• Using lindane after bathing - dramatically increases absorption and seizure risk 4, 1, 2
• Not repeating ivermectin dose at 2 weeks - single dose insufficient due to limited ovicidal activity 1, 2
• Expecting immediate symptom resolution - pruritus may persist 2+ weeks despite cure 1, 2, 8
• Using single-application permethrin for crusted scabies - will fail; requires daily application plus oral ivermectin 2
• Skipping oral ivermectin in crusted scabies - topical alone insufficient given mite burden 2

Reasons for Treatment Failure

When symptoms persist beyond 2-4 weeks, consider:

• Medication resistance (particularly lindane in some regions) 4, 1
• Faulty application technique (incomplete body coverage) 1
• Reinfection from untreated contacts or contaminated fomites 1, 2
• Cross-reactivity with other household mites causing persistent dermatitis 1, 2
• Misdiagnosis - consider alternative diagnoses if no response to appropriate therapy 1

If treatment fails, switch to alternative regimen (e.g., permethrin to ivermectin or vice versa) and ensure all contacts treated simultaneously. 4, 3