Scabies Treatment
The recommended first-line treatment for scabies is 5% permethrin cream applied to the entire body from neck down for 8-14 hours, with a cure rate of 89-95% at 4 weeks after treatment. 1
Treatment Protocol
First-Line Treatment: Permethrin 5% Cream
- Apply thoroughly from head to soles of feet (adults and children)
- For adults, scalp is rarely infested (except hairline, neck, temple, and forehead)
- For infants and geriatric patients, include scalp, temple, and forehead in treatment 2
- Approximately 30 grams is sufficient for an average adult 2
- Leave on for 8-14 hours, then wash off with shower or bath 2
- One application is generally curative 2, though CDC guidelines suggest that a second application after 1 week may be beneficial 1
Alternative Treatment: Oral Ivermectin
- Dosage: 200 μg/kg, repeated in 2 weeks due to limited ovicidal activity 1
- Take with food to increase bioavailability 1
- Efficacy: Single dose provides 62.4-85.9% cure rate at 2 weeks, increasing to 92.8-100% with second dose 3, 4
- Consider when:
- Permethrin treatment fails
- Patient has crusted (Norwegian) scabies
- Compliance with topical treatment is difficult
Important Treatment Considerations
Management of Household Contacts
- Treat all household members and close contacts simultaneously, even if asymptomatic 1
- Include sexual contacts from the previous month 1
- This prevents reinfection and breaks the transmission cycle
Environmental Decontamination
- Machine wash and dry bedding and clothing using hot cycle 1
- Alternatively, remove items from body contact for at least 72 hours 1
Post-Treatment Expectations
- Persistent pruritus after treatment is common and not necessarily a sign of treatment failure 2
- Approximately 75% of patients with persistent pruritus at 2 weeks have resolution by 4 weeks 2
- Retreatment is only indicated if living mites are demonstrable after 14 days 2
Special Populations
- Pregnant or lactating women: Permethrin 5% cream is preferred over ivermectin 1
- Infants and children: Permethrin 5% cream is safe and effective in children 2 months and older 2
- Elderly patients: No dosage adjustment needed, though they may need treatment of the hairline and forehead 2
Treatment Efficacy Comparison
Permethrin 5% cream shows superior efficacy compared to alternatives:
- Permethrin vs. Ivermectin: Two applications of permethrin with a one-week interval is more effective (96.9%) than a single dose of oral ivermectin (62.4%) 4
- Permethrin application technique: Applying permethrin as cold cream for two consecutive days (87.2% cure rate) is more effective than a single application (61.8%) 5
Common Pitfalls and Caveats
- Failure to treat all contacts: One of the most common reasons for treatment failure
- Inadequate application: Ensure thorough coverage of all skin areas
- Misinterpreting persistent pruritus: Post-scabetic itch may persist for weeks and is not an indication for retreatment 2
- Insufficient follow-up: Evaluate after 1 week if symptoms persist; retreatment may be necessary if mites are still detected 1
- Potential side effects: Permethrin may cause mild local reactions, temporary exacerbation of pruritus, edema, and erythema 2
Remember that scabies infestation is often accompanied by pruritus, edema, and erythema, and treatment with permethrin may temporarily exacerbate these conditions 2. However, permethrin has low mammalian toxicity and minimal allergic side effects, making it a safe choice for most patients 1.