What concentration of permethrin cream is recommended to treat potential scabies?

Permethrin 5% Cream is the Recommended Concentration for Treating Scabies

For potential scabies, permethrin 5% cream should be applied to all areas of the body from the neck down (or scalp-to-toes in certain cases) and washed off after 8-14 hours. 1, 2

Dosage and Application Instructions

• Apply permethrin 5% cream thoroughly to the entire body:
  • Adults and older children: Apply from neck down to soles of feet
  • Infants and geriatric patients: Include the scalp, hairline, neck, temple, and forehead 1, 2, 3
• Approximately 30 grams is sufficient for an average adult 2
• Leave the cream on for 8-14 hours before washing off with shower or bath 1, 2
• One application is generally curative, with cure rates of 89-95% at 4 weeks after treatment 1, 2

Important Considerations

• Scalp application: While scabies rarely infests the scalp of adults, consider scalp-to-toes application in cases with head involvement, infants, or geriatric patients 3
• Persistent pruritus: Patients may experience persistent itching after treatment, which is rarely a sign of treatment failure and not an indication for retreatment 2
• Retreatment: Only necessary if living mites are demonstrable after 14 days 2
• Environmental measures: Decontaminate bedding and clothing by machine washing and drying using hot cycle, or remove items from body contact for at least 72 hours 1

Special Populations

• Permethrin 5% cream is safe and recommended for:
  • Pregnant women
  • Breastfeeding women
  • Infants and children 1

Treatment of Household Contacts

• Treat all household members and close contacts simultaneously, even if asymptomatic 1
• Include sexual contacts from the previous month to prevent reinfection 1
• Avoid sexual contact until patients and partners have been treated 1

Follow-Up

• Evaluate after 1 week if symptoms persist 1
• Retreatment may be necessary if:
  • Mites are still detected
  • No clinical response is achieved with initial treatment 1

Common Pitfalls to Avoid

1. Undertreating: Ensure thorough application to all body areas, including often-missed areas like finger webs, umbilicus, and genital regions
2. Incorrect concentration: Do not confuse with permethrin 1% cream rinse, which is used for pediculosis (lice) 1
3. Premature retreatment: Persistent itching after treatment is common and not necessarily an indication for retreatment 2
4. Neglecting environmental measures: Failure to decontaminate bedding and clothing can lead to reinfection 1
5. Missing head involvement: In infants, elderly, or severe cases, the scalp may need treatment despite traditional neck-down recommendations 3

Permethrin 5% cream has low mammalian toxicity and minimal allergic side effects, making it the preferred first-line treatment for scabies across all age groups 1, 4.