What is the recommended treatment for scabies with deep burrows?

Treatment of Scabies with Deep Burrows

Permethrin 5% cream applied from the neck down for 8-14 hours is the first-line treatment for scabies with deep burrows, with one application generally being curative. 1, 2, 3, 4

First-Line Treatment Approach

Standard scabies (including deep burrows) should be treated with topical permethrin 5% cream as follows:

• Apply to all areas of the body from the neck down, ensuring coverage of burrows and all skin folds 1, 2, 3
• Leave on for 8-14 hours, then wash off 1, 2, 3
• In infants, include the scalp in the application area 1
• One application is generally curative for uncomplicated scabies 1, 3

Critical application technique to avoid treatment failure:

• Must include under nails, all body folds, and up to the edge of all orifices 1
• Inadequate topical application is a common cause of treatment failure 1

Alternative Treatment Option

Oral ivermectin 200 μg/kg is an effective alternative, particularly useful when topical application is impractical:

• Take with food to increase bioavailability and epidermal penetration 1, 2
• Must repeat the dose in 2 weeks—this is essential for complete eradication 1, 2
• Not recommended for children weighing less than 15 kg due to potential neurotoxicity 3
• The two-dose regimen addresses ivermectin's limited ovicidal activity 2

Special Situation: Crusted (Norwegian) Scabies

If the deep burrows are part of crusted scabies (thick, hyperkeratotic lesions with massive mite burden), combination therapy is mandatory:

• Topical 5% permethrin cream applied daily for 7 days, then twice weekly until cure 1, 2, 3
• PLUS oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 1, 2, 3
• Single-application permethrin as used for ordinary scabies will fail in crusted scabies 2
• Topical therapy alone is insufficient given the mite burden and thick crusts 2

Essential Contact and Environmental Management

Simultaneous treatment of all contacts is non-negotiable:

• All persons with close personal, sexual, or household contact within the preceding month must be examined and treated simultaneously, even if asymptomatic 1, 2, 3
• Failure to treat contacts simultaneously is the most common cause of treatment failure 1

Environmental decontamination:

• Machine wash/dry bedding and clothing on hot cycle, or dry clean 1, 2
• Alternatively, remove items from body contact for at least 72 hours 1, 2
• Fumigation of living areas is unnecessary 2

Expected Post-Treatment Course

Persistent symptoms do NOT indicate treatment failure:

• Rash and pruritus may persist for up to 2 weeks after successful treatment 1, 2, 3, 4
• This is a normal inflammatory response and does NOT require retreatment 1, 2
• Approximately 75% of patients with pruritus at 2 weeks will have resolution by 4 weeks 4

Retreatment is indicated ONLY if:

• Symptoms persist beyond 2 weeks AND demonstrable living mites are observed after 14 days 1, 2, 3

Treatments to Avoid

Lindane 1% should be avoided due to neurotoxicity risk:

• Contraindicated in children <10 years, pregnant/lactating women, and persons with extensive dermatitis 1, 2, 3
• Never use lindane after bathing, as this increases absorption and neurotoxicity risk 1, 2

Common Pitfalls

• Not treating all close contacts simultaneously—the leading cause of treatment failure 1
• Inadequate topical application—missing body folds, under nails, or facial areas in infants 1
• Not repeating ivermectin at 2 weeks when using oral therapy 1
• Expecting immediate symptom resolution—pruritus persists up to 2 weeks normally 1, 4
• Using single-dose therapy for crusted scabies—requires aggressive combination approach 2