Scabies Treatment
Topical permethrin 5% cream is the first-line treatment for uncomplicated scabies, applied from the neck down for 8-14 hours, with one application generally being curative. 1, 2
First-Line Treatment Options
Topical Permethrin 5% Cream
- Apply to all areas of the body from the neck down, including skin folds and creases 1, 2
- Leave on for 8-14 hours (overnight application), then wash off 1, 2
- Pay particular attention to areas under fingernails, between fingers, wrists, axillary folds, abdomen, buttocks, and genitalia 2
- One application is generally curative, though a second application may be considered after 1-2 weeks if needed 1
- Safe for use in infants as young as 2 months of age 3
Oral Ivermectin
- Dose: 200 μg/kg body weight, repeated in 2 weeks 1, 2
- Must be taken with food to increase bioavailability and epidermal penetration 2
- Contraindicated in children weighing less than 15 kg due to neurotoxicity risk 1
- No dosage adjustment needed for renal impairment 2
- Particularly useful for treatment failures, immunocompromised patients, and mass treatment in institutional settings 1, 2
Special Populations
Pregnant and Lactating Women
- Permethrin is the preferred and only recommended treatment 1, 2
- Avoid ivermectin due to limited safety data in pregnancy and lactation 1
- Permethrin shows no evidence of harm to the fetus in animal studies and is Pregnancy Category B 3
Infants and Young Children
- Permethrin is the treatment of choice for children ≥2 months of age 1, 3
- Avoid ivermectin in children weighing <15 kg 1
- Safety and effectiveness in infants <2 months have not been established 3
Crusted (Norwegian) Scabies
- Requires combination therapy: 1, 2
- This severe form occurs primarily in immunocompromised patients and requires aggressive treatment 2
Contact Management and Environmental Decontamination
Contact Tracing and Treatment
- All persons with close personal, sexual, or household contact within the preceding month must be examined and treated, even if asymptomatic 1, 2
- Failure to treat contacts simultaneously is the most common cause of treatment failure 2
Environmental Measures
- Machine wash and dry bedding and clothing using hot cycle, or dry clean 2
- Alternatively, remove items from body contact for at least 72 hours 2
- Fumigation of living areas is unnecessary 2
Follow-Up and Persistent Symptoms
Expected Post-Treatment Course
- Rash and pruritus may persist for up to 2 weeks after successful treatment 1, 2
- Approximately 75% of patients with pruritus at 2 weeks will have resolution by 4 weeks 3
- Persistent symptoms do NOT indicate treatment failure during this period 2
When to Retreat
- Consider retreatment only after 2 weeks if symptoms persist AND live mites are observed 1, 2
- Reasons for persistent symptoms include: treatment failure, reinfection from untreated contacts, inadequate application, and cross-reactivity with other household mites 2
Critical Pitfalls to Avoid
Application Errors
- Inadequate coverage of all body areas, particularly under fingernails and in skin folds 2
- Not applying permethrin to the entire body from neck down 1
- Failure to repeat ivermectin dose at 2 weeks 2
Medication-Specific Warnings
- Avoid lindane in children <10 years, pregnant/lactating women, and persons with extensive dermatitis due to severe neurotoxicity risk 1, 2
- Never use lindane after bathing, as this increases absorption and toxicity 2
- Avoid eye contact with permethrin; flush immediately with water if contact occurs 3