What is the recommended treatment for scabies management?

Scabies Management

First-Line Treatment Recommendation

Permethrin 5% cream applied to all areas of the body from the neck down and washed off after 8-14 hours is the recommended first-line treatment for scabies in most patients. 1, 2, 3

Oral ivermectin 200 μg/kg, repeated in 2 weeks, is an equally effective first-line alternative, particularly useful for institutional outbreaks, patients who cannot tolerate topical therapy, or those with difficulty applying cream to all body surfaces. 1, 2, 3

Treatment Algorithm by Patient Population

Standard Adult Patients

• Apply permethrin 5% cream from neck down to entire body surface, including under fingernails, in skin folds, and between fingers and toes 1, 2
• Leave on for 8-14 hours (overnight application is practical) 1, 2
• Repeat application in 7-10 days 1
• Alternative: Oral ivermectin 200 μg/kg taken with food, repeated exactly 14 days later 1, 2, 3

Infants and Young Children

• Use permethrin 5% cream only—this is the safest option 1, 2
• Permethrin is safe in children ≥2 months of age 4
• Never use lindane in children <10 years due to neurotoxicity risk 1, 2, 3
• Ivermectin should not be used in children <10 years 1

Pregnant and Lactating Women

• Permethrin 5% cream is the preferred treatment 1, 2, 5
• Permethrin is Pregnancy Category B with no evidence of fetal harm 4
• Ivermectin is classified as "human data suggest low risk" in pregnancy and probably compatible with breastfeeding 1
• Avoid lindane completely—associated with neural tube defects and mental retardation 1

Crusted (Norwegian) Scabies

This requires aggressive combination therapy due to massive mite burden (thousands to millions of mites): 3

• Permethrin 5% cream applied daily for 7 days, then twice weekly until cure 2, 3
• PLUS oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 2, 3
• Single-dose regimens will fail in crusted scabies 3
• This occurs in immunocompromised, debilitated, or malnourished patients and is far more contagious than typical scabies 3

Immunocompromised Patients

• Higher risk for crusted scabies and treatment failure 2, 3
• Consider combination therapy even if not overtly crusted 3
• Closer monitoring necessary 3

Alternative Treatment Options (When First-Line Fails or Is Unavailable)

Benzyl Benzoate 25%

• Recent high-quality evidence shows 87% cure rate compared to only 27% for permethrin in a head-to-head trial 6
• Consider this when permethrin fails or resistance is suspected 2, 6
• Applied to entire body, repeated after 24 hours 2
• Causes burning sensation in 43% of patients but has excellent efficacy 2, 6

Lindane 1%

• Use only as last resort when other therapies have failed or cannot be tolerated 1, 2
• Applied thinly from neck down, washed off after 8 hours 1, 2
• Critical contraindications: 1, 2, 3
  • Children <10 years (neurotoxicity risk)
  • Pregnant or lactating women (neural tube defects, mental retardation)
  • Persons with extensive dermatitis (increased absorption, seizure risk)
  • Never apply after bathing (increases absorption and seizure risk)
• Resistance reported in some U.S. regions 1

Sulfur 6% Ointment

• Applied nightly for 3 nights, washing off previous applications before reapplying 2
• Safe alternative for pregnant women and infants 2

Crotamiton 10%

• Applied nightly for 2 consecutive nights, washed off 24 hours after second application 3, 7
• Less effective than permethrin or ivermectin 7

Critical Management Components Beyond Medication

Contact Tracing and Treatment

• Examine and treat ALL sexual, close personal, and household contacts within the preceding month simultaneously 1, 2, 3
• Failure to treat contacts simultaneously is a leading cause of treatment failure 2, 3
• For institutional outbreaks, treat the entire at-risk population 2

Environmental Decontamination

• Machine wash and dry all bedding and clothing using hot cycle 1, 2, 3
• Alternative: dry clean or remove from body contact for at least 72 hours 1, 2, 3
• Fumigation of living areas is unnecessary 1, 2, 3
• Keep fingernails closely trimmed to reduce injury from scratching 1, 2

Ivermectin-Specific Instructions

• Must be taken with food to increase bioavailability and epidermal penetration 1, 3
• Second dose at exactly 14 days is mandatory (addresses limited ovicidal activity) 1, 2, 3
• No dosage adjustment needed for renal impairment 3
• Safety of multiple doses in severe liver disease is unknown 1

Follow-Up and Expected Course

Normal Post-Treatment Symptoms

• Pruritus may persist for up to 2 weeks after successful treatment—this does NOT indicate treatment failure 2, 3, 5, 4
• In clinical trials, approximately 75% of patients with persistent pruritus at 2 weeks had resolution by 4 weeks 4
• Treatment may temporarily exacerbate pruritus, edema, and erythema 4

When to Consider Retreatment

Evaluate after 1 week if symptoms persist; consider retreatment after 2 weeks if: 1, 2, 3

• Live mites are observed on dermoscopy or microscopy
• New burrows appear
• Symptoms worsen rather than gradually improve

Common Reasons for Treatment Failure

• Failure to treat all close contacts simultaneously 2, 3
• Inadequate application of topical treatments (missing skin folds, under nails, between toes) 2, 3
• Reinfection from untreated contacts or contaminated fomites 2, 3
• True medication resistance (particularly with permethrin) 2, 6
• Using lindane after bathing or in contraindicated populations 2, 3
• Not repeating ivermectin dose after 2 weeks 2, 3

Emerging Evidence on Permethrin Resistance

Recent 2024 data shows concerning permethrin failure rates: 6

• Head-to-head trial demonstrated only 27% cure rate with permethrin 5% vs. 87% with benzyl benzoate 25% 6
• This suggests reduced sensitivity of scabies mites to permethrin in some populations 6
• If permethrin fails, switch to benzyl benzoate or ivermectin rather than repeating permethrin 2, 6

Special Application Techniques

Optimizing Permethrin Application

• Apply to completely dry skin (not after bathing) 1, 3
• Some evidence suggests applying cold cream (stored in refrigerator) and leaving on for 24 hours may improve efficacy 8
• Two consecutive daily applications may be more effective than single application (87.2% vs. 61.8% cure rate) 8

Secondary Bacterial Infection

• If impetiginization is present (crusting, honey-colored exudate), consider adding topical fusidic acid 2% cream 9
• Most common organisms: Staphylococcus aureus and Streptococcus pyogenes 10, 9
• Combination permethrin 5% + fusidic acid 2% showed 95% efficacy vs. 35% for permethrin alone at day 14 in impetiginized scabies 9