What is the recommended treatment for scabies?

Recommended Treatment for Scabies

Permethrin 5% cream is the first-line treatment for scabies, applied from neck to feet (head-to-toe in infants and elderly), left on for 8-14 hours, and then washed off. 1, 2

First-Line Treatment

• Permethrin 5% cream:
  • Application: Thoroughly massage into skin from head (or neck in adults) to soles of feet
  • Duration: Leave on for 8-14 hours, then wash off with shower or bath
  • Dosage: Usually 30 grams is sufficient for an average adult 2
  • Efficacy: Cure rate of 89-95% at 4 weeks after treatment 1
  • Special populations:
    • Infants and geriatric patients: Include scalp, hairline, neck, temple, and forehead in treatment 2
    • Pregnant/lactating women: Preferred over ivermectin due to established safety data 1

Alternative Treatments

1. Oral ivermectin:

   • Dosage: 200 μg/kg body weight
   • Administration: Take with food to increase bioavailability
   • Schedule: Repeat after 14 days (due to limited ovicidal activity)
   • Efficacy: Single dose provides 62.4% cure rate, increasing to 92.8% with second dose 3
   • Note: Less effective than permethrin as a single dose, but comparable when given as two doses 3

2. Other alternatives (when first-line treatments fail or are contraindicated):

   • Benzyl benzoate 25% lotion 4
   • Malathion 0.5% aqueous lotion 4
   • Ivermectin 1% lotion 4
   • Sulphur 6-33% cream, ointment or lotion 4

Treatment Algorithm

1. Standard cases:

   • Apply permethrin 5% cream from neck to feet (include head in infants/elderly)
   • Leave on for 8-14 hours, then wash off
   • One application is generally curative 2

2. For treatment failures:

   • Verify treatment was applied correctly
   • Consider repeating permethrin application after 7-10 days 5
   • Alternative: Switch to oral ivermectin (200 μg/kg) with repeat dose after 14 days 1

3. For crusted (Norwegian) scabies:

   • Combination therapy with topical scabicide AND oral ivermectin 4
   • May require multiple treatments

Important Considerations

• Persistent pruritus:

  • Common after successful treatment (up to 4 weeks)
  • Rarely indicates treatment failure 2
  • Approximately 75% of patients with persistent pruritus at 2 weeks have resolution by 4 weeks 2

• Treatment of contacts:

  • All household members and close contacts should be treated simultaneously, even if asymptomatic 1
  • Look-back period of 2 months for sexual partners 4

• Environmental measures:

  • Decontaminate bedding and clothing by machine washing with hot cycle
  • Items that cannot be washed should be kept out of body contact for at least 72 hours 1

• Follow-up:

  • Retreatment is necessary only if living mites are demonstrable after 14 days 2
  • Evaluate after 1 week if symptoms persist 1

Potential Pitfalls

1. Inadequate application: Ensure complete coverage of all affected areas. Failure to include the head in infants and elderly can lead to treatment failure 6

2. Neglecting contacts: Simultaneous treatment of all household members and close contacts is crucial to prevent reinfection 1

3. Misinterpreting persistent pruritus: Itching may continue for weeks after successful treatment and is not necessarily a sign of treatment failure 2

4. Secondary infections: Consider combination with antibiotics (e.g., fusidic acid 2% cream) when secondary bacterial infection is present, particularly with Staphylococcus aureus 7

5. Contraindications:

   • Avoid ivermectin in children under 15 kg due to limited safety data 1
   • Avoid lindane due to potential neurotoxicity, especially in children under 10 years and pregnant/lactating women 1