What is the recommended treatment for scabies involving the scalp?

Scabies Scalp Treatment

For scabies involving the scalp, permethrin 5% cream should be applied to the entire body including the scalp, temple, and forehead, and washed off after 8-14 hours. 1, 2

First-Line Treatment

Permethrin 5% Cream

• Apply thoroughly from head to toe, including scalp, temple, and forehead 1, 2
• Leave on for 8-14 hours before washing off
• Usually 30 grams is sufficient for an average adult
• One application is generally curative
• FDA-approved drug label specifically states that scabies rarely infests the scalp of adults, although the hairline, neck, temple, and forehead may be infested in infants and geriatric patients 2

Special Considerations for Scalp Involvement

• While traditional guidance has been to apply permethrin from neck down in adults, recent evidence supports scalp-to-toes application, particularly in:
  • Infants and young children
  • Elderly patients
  • Cases with known scalp involvement 3
• Treatment failure can occur when the scalp is not treated in patients with head involvement 3

Alternative Treatments

Oral Ivermectin

• 200 μg/kg orally, repeated in 2 weeks 4
• Not recommended for:
  • Children weighing <15 kg
  • Pregnant women
• Should be taken with food to increase bioavailability and penetration into the epidermis 4

Lindane 1% (Third-Line Option)

• Should only be used if patients cannot tolerate or have failed first-line treatments 4
• Apply thinly to all areas and wash off after 8 hours
• Significant safety concerns:
  • Risk of neurotoxicity, seizures, and aplastic anemia
  • Contraindicated in children <10 years, pregnant/lactating women, and persons with extensive dermatitis 4
  • No longer recommended by the American Academy of Pediatrics 4

Management Protocol

1. Initial Treatment:

   • Apply permethrin 5% cream to entire body including scalp
   • Pay special attention to scalp, temple, and forehead in infants, elderly, and those with known scalp involvement
   • Leave on for 8-14 hours before washing off

2. Environmental Decontamination:

   • Machine wash and dry (using hot cycle) all bedding and clothing
   • Dry clean items that cannot be washed
   • Remove items from body contact for at least 72 hours 1

3. Treatment of Contacts:

   • All household members and close contacts should be treated simultaneously, even if asymptomatic 4, 1
   • Sexual partners within the preceding month should be examined and treated 4

4. Follow-Up:

   • Persistent pruritus may continue for up to 2 weeks after successful treatment
   • Retreatment should be considered if:
     • Symptoms persist beyond 2 weeks
     • Live mites are observed
     • New lesions appear 4, 1

Special Populations

Crusted (Norwegian) Scabies

• Requires combination therapy:
  • Oral ivermectin 200 μg/kg on days 1,2,8,9, and 15
  • Daily application of 5% permethrin cream for 7 days followed by twice weekly applications until cure 1
• Additional ivermectin treatment may be required on days 22 and 29 for severe cases 4

Immunocompromised Patients

• Higher risk for crusted scabies and recurrence
• Should be managed in consultation with a specialist 1

Pregnant Women and Infants

• Permethrin is the preferred treatment during pregnancy and lactation 4
• Safe for use in infants, with special attention to scalp application 1, 2

Treatment Efficacy Concerns

Recent research indicates potential decreasing effectiveness of permethrin in some regions, with one 2024 study showing only 27% cure rate with permethrin compared to 87% with benzyl benzoate 5. This suggests the importance of close follow-up and consideration of alternative treatments if initial therapy fails.