What is the first line treatment for scabies?

First-Line Treatment for Scabies

The first-line treatment for scabies is permethrin 5% cream applied to all areas of the body from the neck down and washed off after 8-14 hours. 1

Treatment Algorithm

First-Line Options:

1. Permethrin 5% cream

   • Application: Apply thoroughly to all areas of the body from the neck down
   • Duration: Leave on for 8-14 hours before washing off
   • Population considerations: Safe for infants, young children, and pregnant women
   • Efficacy: Effective, safe, and less expensive than ivermectin 1
   • Dosing: Usually 30 grams is sufficient for an average adult 2
   • Special populations: In infants, also treat the scalp, temple, and forehead 2

2. Ivermectin (oral)

   • Dosage: 200 μg/kg orally
   • Schedule: Repeated in 2 weeks (due to limited ovicidal activity)
   • Administration: Should be taken with food to increase bioavailability 1
   • Limitations: Not recommended for children <10 years old 1

Alternative Treatment (when first-line fails):

• Lindane 1% (1 oz of lotion or 30 g of cream)
  • Application: Apply thinly to all areas from neck down
  • Duration: Wash off thoroughly after 8 hours
  • Important restrictions: Should only be used if patients cannot tolerate first-line therapies or if these have failed 1
  • Contraindications: Not for use in children <10 years, pregnant/lactating women, persons with extensive dermatitis, or immediately after bathing 1

Additional Management Considerations

Environmental Measures:

• Decontaminate bedding and clothing (machine wash/dry using hot cycle or dry clean)
• Alternatively, remove items from body contact for at least 72 hours
• Fumigation of living areas is unnecessary 1
• Keep fingernails closely trimmed to reduce injury from scratching 1

Follow-Up:

• Be aware that rash and pruritus may persist for up to 2 weeks after successful treatment 1
• Retreatment considerations:
  • If symptoms persist >2 weeks
  • If live mites are observed after treatment 2
  • Consider alternative regimen if initial treatment fails 1

Management of Contacts:

• Both sexual and close personal/household contacts within the preceding month should be examined and treated 1

Special Populations

Pregnant Women:

• Permethrin 5% cream is safe and preferred 1
• Ivermectin is classified as "human data suggest low risk" in pregnancy 1

Infants and Young Children:

• Permethrin is the treatment of choice 1
• Ivermectin and lindane should not be used in children <10 years 1

Crusted (Norwegian) Scabies:

• More aggressive treatment required
• Combination therapy recommended:
  • Topical permethrin 5% cream (daily for 7 days, then 2x weekly until cure)
  • PLUS oral ivermectin on days 1,2,8,9, and 15 (additional doses may be needed) 1

Common Pitfalls and Caveats

1. Persistent symptoms: Pruritus may persist for up to 2 weeks after successful treatment - this is not necessarily treatment failure 1, 2

2. Treatment failure causes:

   • Incorrect application technique
   • Failure to treat all close contacts
   • Reinfestation from untreated contacts or fomites
   • Resistance to medication (particularly with lindane) 1

3. Lindane toxicity risks:

   • Seizures and aplastic anemia have been reported
   • Never use after bathing or in patients with extensive dermatitis 1

4. Comprehensive approach:

   • Treatment of the patient alone is insufficient
   • All household members and close contacts should be treated simultaneously to prevent reinfestation 1