Scabies Treatment
Topical 5% permethrin cream is the first-line treatment for uncomplicated scabies, applied from the neck down (including scalp in infants and elderly), left on for 8-14 hours, then washed off, with one application generally being curative. 1, 2, 3
First-Line Treatment Options
Permethrin 5% Cream (Preferred)
- Apply to all skin surfaces from the neck down, massaging thoroughly into the skin 3
- In infants, young children, and geriatric patients, also treat the scalp, hairline, neck, temple, and forehead since these areas can be infested in these populations 1, 3
- Leave on for 8-14 hours before washing off 1, 2, 3
- Approximately 30 grams is sufficient for an average adult 3
- One application is generally curative 1, 3
- Repeat treatment after 7-10 days if needed 2
Oral Ivermectin (Alternative First-Line)
- Dose: 200 μg/kg, repeated in 2 weeks 1, 2
- Must be taken with food to increase bioavailability and epidermal penetration 2, 4
- Contraindicated in children weighing less than 15 kg due to neurotoxicity risk 1, 4
- No dosage adjustment needed for renal impairment 2
Special Populations
Pregnant and Lactating Women
- Use permethrin exclusively as the preferred treatment 1, 2, 4
- Avoid ivermectin due to limited safety data in these populations 1, 4
Infants and Young Children
- Permethrin is the treatment of choice 1, 2, 4
- Must include scalp, temple, and forehead in application 3
- Avoid ivermectin in children <15 kg 1, 4
Crusted (Norwegian) Scabies
Requires combination therapy with both topical and oral agents 1, 2:
- 5% permethrin cream applied daily for 7 days, then twice weekly until cure 2
- Plus oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2
- Immunocompromised patients require closer monitoring for treatment failure 2
Contact and Environmental Management
Contact Tracing and Treatment
- Examine and treat all persons with close personal, sexual, or household contact within the preceding month, even if asymptomatic 1, 2, 4
- Failure to treat all contacts simultaneously is the most common cause of treatment failure 4
- Use a 2-month look-back period for partner management 5
Environmental Decontamination
- Machine wash and dry bedding/clothing using hot cycle, or dry clean 2, 4
- Alternatively, remove items from body contact for at least 72 hours 2, 4
- Fumigation of living areas is unnecessary 2, 4
Follow-Up and Persistent Symptoms
Expected Post-Treatment Course
- Rash and pruritus may persist for up to 2 weeks after successful treatment and this does not indicate treatment failure 1, 2, 3
- Persistent pruritus after treatment is rarely a sign of treatment failure 3
When to Retreat
- Consider retreatment only after 2 weeks if symptoms persist AND live mites are observed 1, 2, 4
- Demonstrable living mites after 14 days indicate retreatment is necessary 3
Critical Pitfalls to Avoid
Application Errors
- Failure to apply permethrin to all body areas, including under nails and to the edge of all body orifices 4
- Not treating the scalp and face in infants and elderly patients 3
- Not repeating the ivermectin dose at 2 weeks, which is essential for complete eradication 4
Medication-Specific Warnings
- Avoid lindane in children <10 years, pregnant/lactating women, and persons with extensive dermatitis due to neurotoxicity risk 1, 2, 4
- Never use lindane after bathing, as this increases absorption and toxicity risk 2, 4