What is the recommended treatment for scabies in an otherwise healthy individual?

Treatment for Scabies

Permethrin 5% cream applied from the neck down (or scalp-to-toes in infants, elderly, and immunocompromised patients) and washed off after 8-14 hours is the first-line treatment for scabies in otherwise healthy individuals. 1, 2, 3

First-Line Treatment: Permethrin 5% Cream

Permethrin 5% cream is the gold standard therapy, being more effective, safer, and less expensive than ivermectin for standard scabies. 1

Application Instructions

• Apply thoroughly to all areas of the body from the neck down, massaging into the skin with particular attention to folds and creases 1, 3
• Wash off after 8-14 hours (shower or bath) 1, 3
• Usually 30 grams is sufficient for an average adult 3
• One application is generally curative, though a second application may be considered 3

Special Application Requirements for High-Risk Groups

• Infants, elderly, and immunocompromised patients require scalp-to-toes application, including hairline, neck, temple, and forehead 1, 4
• This expanded application is critical because these populations can have head and scalp involvement that would be missed with neck-down application only 1, 4

Alternative First-Line Treatment: Oral Ivermectin

Oral ivermectin 200 μg/kg body weight is an alternative first-line option, particularly useful for institutional outbreaks, bedridden patients, or when topical application is impractical. 1, 2

Dosing Protocol

• Take with food to increase bioavailability and epidermal penetration 1, 2
• Repeat the second dose after 2 weeks - this is essential because ivermectin has limited ovicidal activity and does not kill eggs present at initial treatment 1, 2
• Not repeating the second dose is a common treatment failure pitfall 1

Comparative Efficacy

• A single dose of ivermectin provides only 62.4% cure rate, increasing to 92.8% with two doses at 2-week intervals 5
• Two applications of permethrin (one week apart) achieves 96.9% cure rate 5
• Permethrin-treated patients recover earlier than ivermectin-treated patients 5

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

Benzyl Benzoate 25%

• Shows 87% cure rate but may cause burning sensation in 43% of patients 1
• Consider when permethrin fails or is unavailable 1, 6

Crotamiton 10%

• Apply nightly for 2 consecutive nights, wash off 24 hours after second application 1, 7

Sulfur 6% Ointment

• Apply thinly to affected areas nightly for 3 nights, washing off previous applications before reapplying 1

Lindane 1% (Use with Extreme Caution)

• Contraindicated in children <10 years, pregnant/lactating women, and persons with extensive dermatitis due to neurotoxicity risk 1, 2
• Should not be used after bathing, as this increases absorption and seizure risk 1, 2

Special Populations

Pregnant and Lactating Women

• Permethrin 5% cream is the preferred treatment 1, 2, 6
• Ivermectin is classified as "human data suggest low risk" in pregnancy and probably compatible with breastfeeding, but permethrin remains preferred 1

Infants and Young Children

• Use permethrin 5% cream with scalp-to-toes application 1
• Avoid lindane completely due to neurotoxicity risk 1, 2

Immunocompromised Patients

• Higher risk for crusted (Norwegian) scabies requiring more aggressive treatment 1, 2
• Require scalp-to-toes permethrin application 1

Crusted (Norwegian) Scabies Management

Crusted scabies requires aggressive combination therapy because single-dose topical or oral treatment alone will fail. 2

Treatment Protocol

• 5% permethrin cream applied daily for 7 days, then twice weekly until cure 1, 2
• PLUS oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2
• The multiple-dose ivermectin schedule addresses the massive mite burden (thousands to millions of mites) and ivermectin's limited ovicidal activity 2

Critical Environmental and Contact Management

Contact Treatment

• Examine and treat ALL persons who have had sexual, close personal, or household contact within the preceding month 1, 2
• Failure to treat all close contacts simultaneously is the most common cause of treatment failure 1, 2
• For institutional outbreaks, treat the entire population at risk 1

Environmental Decontamination

• Machine wash and dry bedding and clothing using hot cycle, OR dry clean, OR remove from body contact for at least 72 hours 1, 2, 6
• Fumigation of living areas is unnecessary 1, 2
• Keep fingernails closely trimmed to reduce injury from scratching 1

Follow-Up and Management of Persistent Symptoms

Expected Post-Treatment Course

• Pruritus may persist for up to 2 weeks after successful treatment and is NOT a sign of treatment failure 1, 2, 3
• Persistent pruritus alone is NOT an indication for retreatment 1

When to Consider Retreatment

• Consider retreatment if symptoms persist beyond 2 weeks AND live mites are observed 1, 2
• Demonstrable living mites after 14 days indicate that retreatment is necessary 3

Reasons for Treatment Failure

• Resistance to medication 1
• Faulty application of topical treatments (inadequate coverage, missing scalp in high-risk groups) 1, 2
• Reinfection from untreated contacts or fomites 1, 2
• Cross-reactivity with other household mites 1, 2

Common Treatment Pitfalls to Avoid

• Failure to treat all close contacts simultaneously 1, 2
• Inadequate application of topical treatments (missing body areas, insufficient quantity) 1, 2
• Using lindane after bathing or in contraindicated populations 1, 2
• Not repeating ivermectin dose after 2 weeks 1, 2
• Expecting immediate resolution of symptoms (may take up to 2 weeks) 1, 2
• Applying only neck-down in elderly or immunocompromised patients (should be scalp-to-toes) 1, 4

Management of Secondary Bacterial Infection

If impetiginized scabies is present (secondary bacterial infection), combining permethrin 5% with fusidic acid 2% cream is more effective than permethrin alone. 8

• The most common bacterium causing secondary infection is Staphylococcus aureus 8
• Treatment efficacy on day 14 is 95% with combination therapy versus 35% with permethrin alone 8