What is the recommended treatment for a patient with scabies?

Scabies Treatment

First-Line Treatment Recommendation

Permethrin 5% cream is the preferred first-line treatment for scabies in otherwise healthy individuals, applied from the neck down and washed off after 8-14 hours. 1, 2, 3

Treatment Algorithm by Clinical Context

Standard Scabies (Immunocompetent Patients)

Primary Option:

• Permethrin 5% cream applied to all body areas from neck down, washed off after 8-14 hours 1, 2
• Permethrin is more effective, safer, and less expensive than ivermectin for standard scabies 1
• A second application may be considered if symptoms persist beyond 2 weeks 1

Alternative Option:

• Oral ivermectin 200 μg/kg body weight, with mandatory second dose after 2 weeks 1, 2
• Must be taken with food to increase bioavailability and epidermal penetration 1, 2
• The second dose is essential because ivermectin has limited ovicidal activity and does not kill eggs present at initial treatment 1

Special Populations

Pregnant or Lactating Women:

• Permethrin 5% cream is the preferred and safest option 1, 2, 3
• 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:

• Permethrin 5% cream is recommended 1, 3
• Critical application difference: Must apply scalp-to-toes including hairline, neck, temple, and forehead (not just neck down as in adults) 1
• Permethrin is safe in children ≥2 months of age 4
• Avoid lindane in children <10 years due to neurotoxicity risk 1, 2

Elderly and Immunocompromised:

• Require scalp-to-toes application of permethrin 5% cream 1
• Higher risk for crusted (Norwegian) scabies requiring more aggressive treatment 1

Crusted (Norwegian) Scabies

Combination therapy is mandatory:

• Permethrin 5% 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
• Single-application permethrin or single-dose ivermectin will fail in crusted scabies 2
• This aggressive approach addresses the massive mite burden (thousands to millions of mites) 2

Alternative Treatments (When First-Line Options Unavailable)

• Lindane 1%: Applied thinly from neck down, washed off after 8 hours 1

  • Contraindications: Children <10 years, pregnant/lactating women, extensive dermatitis, post-bathing application 1, 2
  • Risk of neurotoxicity and seizures in contraindicated populations 1, 2

• Sulfur 6% ointment: Applied nightly for 3 nights, washing off previous applications before reapplying 1

• Crotamiton 10%: Applied nightly for 2 consecutive nights, washed off 24 hours after second application 1, 5

• Benzyl benzoate 25%: 87% cure rate but causes burning sensation in 43% of patients 1

Essential Contact and Environmental Management

Contact Treatment (Critical to Prevent Reinfection):

• Treat all sexual, close personal, and household contacts within the preceding month simultaneously 1, 2, 3
• For institutional outbreaks, treat the entire at-risk population 1

Environmental Decontamination:

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

Follow-Up and Retreatment Criteria

Expected Post-Treatment Course:

• Pruritus may persist for up to 2 weeks after successful treatment 1, 2
• Approximately 75% of patients with persistent pruritus at 2 weeks will have resolution by 4 weeks 4
• Persistent pruritus alone is NOT an indication for retreatment 1

Retreatment Indications:

• Live mites observed on examination 1, 2
• Symptoms persist beyond 2 weeks with clinical signs of active infestation 1, 2
• New burrows or lesions appearing 1

Evaluation Timeline:

• Evaluate at 1 week if symptoms are severe 2
• Evaluate at 2 weeks for persistent symptoms to determine retreatment need 1, 2

Critical Treatment Pitfalls to Avoid

1. Failure to treat all close contacts simultaneously - most common cause of treatment failure 1, 2
2. Inadequate topical application - must cover all areas as directed 1, 2
3. Not repeating ivermectin dose after 2 weeks - essential due to limited ovicidal activity 1, 2
4. Using lindane after bathing - increases absorption and seizure risk 1, 2
5. Using lindane in contraindicated populations - children <10 years, pregnant/lactating women, extensive dermatitis 1, 2
6. Expecting immediate symptom resolution - pruritus may persist 2 weeks normally 1, 2, 4
7. Single-dose therapy for crusted scabies - will fail without combination approach 2
8. Failure to decontaminate fomites - leads to reinfection 1, 6

Adjunctive Symptomatic Management

Topical corticosteroids (e.g., triamcinolone):

• Should NOT be used during active treatment phase 2
• May suppress inflammatory response needed to identify active infestation 2
• Only consider after treatment completion if pruritus persists beyond 2 weeks AND live mites are confirmed absent 2
• Use limited application to minimize risks of atrophy, pigmentary changes, and telangiectasias 2

Treatment Failure Evaluation

Common reasons for persistent symptoms:

• Resistance to medication (rare) 1
• Faulty application of topical treatments 1, 2
• Reinfection from untreated contacts or fomites 1, 2
• Cross-reactivity with other household mites 1, 2
• Misdiagnosis (consider alternative diagnoses) 6