How should I educate a patient with scabies about treatment with permethrin 5% cream, alternative ivermectin use, contact prophylaxis, environmental cleaning, expected post‑treatment itching, and indications for further medical review?

Patient Education for Scabies Treatment

Permethrin 5% Cream Application Instructions

Apply permethrin 5% cream from the neck down to the entire body surface, including under fingernails, between toes, and all skin folds, leave on for 8–14 hours (overnight), then wash off with warm water in the morning. 1, 2

Age-Specific Application Differences

• Infants and children under 2 years require scalp-to-toes application, including the hairline, forehead, temples, and neck, because scabies commonly affects the head in this age group. 1
• Children ≥10 years and adults apply from neck down only, unless immunocompromised. 1
• A single application is generally curative in uncomplicated cases. 2

Critical Application Technique

• Ensure coverage of all body surfaces, particularly under fingernails, between fingers and toes, in skin folds, and around all body orifices. 1
• Rinse off over a sink with warm (not hot) water to minimize systemic absorption. 3

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Alternative Treatment: Oral Ivermectin

Oral ivermectin 200 μg/kg is an effective alternative to permethrin and must be repeated after 2 weeks to address newly hatched mites. 1, 2

Contraindications and Precautions

• Never use ivermectin in children weighing <15 kg or younger than 10 years due to risk of neurotoxicity from blood-brain barrier penetration. 1
• Always take ivermectin with food to ensure adequate bioavailability; absorption is markedly reduced on an empty stomach. 1, 2
• Ivermectin is contraindicated in pregnancy and lactation due to insufficient safety data. 1, 2

When to Consider Ivermectin

• Ivermectin is particularly useful when topical application is impractical, such as in institutional outbreaks or when patients cannot reliably apply cream. 1

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Contact Prophylaxis: Mandatory Simultaneous Treatment

All household members, close contacts, and sexual partners from the preceding month must be treated simultaneously, even if completely asymptomatic, to prevent reinfection. 1, 2

• Failure to treat asymptomatic contacts is the most common cause of treatment failure and reinfection. 1, 2
• Use the same treatment regimen for all contacts as used for the index patient. 1

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Environmental Cleaning Requirements

Machine-wash all bedding, clothing, and towels in hot water and dry on the hottest cycle; alternatively, dry-clean items or isolate them from skin contact for at least 72 hours. 1, 2

What Is NOT Required

• Fumigation of living areas is completely unnecessary because scabies mites cannot survive off human skin for more than 72 hours. 1, 2
• Focus cleaning efforts on items with direct skin contact only. 1

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Expected Post-Treatment Itching: Normal vs. Treatment Failure

Itching and rash commonly persist for up to 2 weeks after successful treatment due to allergic dermatitis from dead mites and is NOT a sign of treatment failure. 1, 2

Managing Post-Treatment Symptoms

• Topical corticosteroids (such as triamcinolone) and oral antihistamines may relieve persistent itching after confirming no live mites remain. 3, 2
• Do not apply corticosteroids during active treatment, as this may suppress the inflammatory response needed to identify active infestation. 2

When Symptoms Are Normal

• Continued itching for 1–2 weeks is expected and does not require retreatment. 1, 2
• New skin lesions may appear briefly as the immune system reacts to dying mites. 1

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Indications for Further Medical Review

Return for medical evaluation only if any of the following occur:

Definite Retreatment Criteria (After 2 Weeks)

• Live mites are observed on skin examination after 2 weeks. 1, 2
• Symptoms persist beyond 2 weeks post-treatment. 1, 2
• New lesions continue to appear after 2 weeks. 1

When to Switch Treatment

• If retreatment is needed, switch between permethrin and ivermectin (e.g., if permethrin failed, use ivermectin, and vice versa). 1

Common Pitfall to Avoid

• Do not seek retreatment within the first 2 weeks based solely on persistent itching, as this is expected and does not indicate treatment failure. 1, 2

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Treatments to Avoid

Never use lindane, especially in children <10 years, pregnant or lactating women, or anyone with extensive skin inflammation, due to high risk of seizures and neurotoxicity. 1, 2

• Lindane is no longer recommended by the American Academy of Pediatrics and is banned in California. 3
• Applying lindane after bathing dramatically increases systemic absorption and toxicity risk. 2