What is the management for a 5-year-old child with pediculosis (head lice)?

Management of Head Lice in a 5-Year-Old Child

Treat the child immediately with permethrin 1% cream rinse applied to damp, towel-dried hair for exactly 10 minutes, then rinse off, and repeat the application in 7-10 days. 1, 2

Immediate Treatment Protocol

First-Line Treatment: Permethrin 1%

• Apply permethrin 1% cream rinse to damp (not soaking wet), towel-dried hair after shampooing with non-conditioning shampoo 1, 2
• Leave on for exactly 10 minutes—no longer 1, 2
• Rinse thoroughly with warm water over a sink (not in shower/bath) to limit skin exposure 1
• A mandatory second application must be done in 7-10 days to kill newly hatched nymphs, as permethrin has only 70-80% ovicidal activity 1, 2
• This medication has low mammalian toxicity and does not cause allergic reactions in patients with plant allergies 1, 2

Nit Removal (Adjunctive)

• After treatment, towel dry hair and comb out tangles 3
• Apply vinegar or vinegar-based products to hair for 3 minutes before combing to help loosen nits 1
• Use a fine-tooth nit comb, working on 1-2 inch sections of hair at a time, placing comb as close to scalp as possible 3
• While nit removal is not necessary to prevent spread, it helps decrease diagnostic confusion 2

Household Management

Who to Examine and Treat

• Examine all household members for lice, but only treat those with live lice or eggs within 1 cm of scalp 1, 2
• Treat family members who share a bed with the infected child 2

Environmental Decontamination

• Wash all clothing, bedding, and linens in hot water and dry on hot cycle on the same day as treatment 2
• Wash hair care items (brushes, combs) in hot water 2
• Remove items that cannot be washed from body contact for at least 72 hours, as lice cannot survive off the human body for more than 2-3 days 2

Follow-Up and Treatment Failure

Expected Post-Treatment Course

• Post-treatment itching persists for days and is NOT a sign of treatment failure—do not retreat based on itching alone 1, 2
• Itching or mild burning of scalp after treatment is common and can be relieved with topical corticosteroids or oral antihistamines 1, 2
• Check daily for any lice/nits that were missed 3

Assessing Treatment Success

• At 2 weeks post-treatment, examine the scalp for live lice 2
• Only retreat if live lice are seen 7-10 days after treatment 2
• Before assuming resistance, consider misdiagnosis, noncompliance, reinfestation, or improper application technique as the first cause of treatment failure 1, 2

Second-Line Options (If First-Line Fails)

When Permethrin Fails Despite Proper Use

• Malathion 0.5% lotion is the second-line treatment when resistance to permethrin is documented or when first-line treatments fail despite correct use 1, 2
• Apply to dry hair, allow to air dry naturally, then wash off after 8-12 hours 2
• Has the highest ovicidal activity of all treatments 1, 2
• Contains 78% isopropyl alcohol making it highly flammable—do not use near open flames, sparks, or heat sources 2
• Cannot be used in children under 24 months 4

Alternative First-Line Option

• Spinosad 0.9% topical suspension achieves high cure rates with a single 10-minute application to dry hair 1

Critical Pitfalls to Avoid

• Never treat without confirming live lice or nits within 1 cm of scalp—nits may remain glued to hair for at least 6 months after successful treatment, leading to false positive diagnosis 1, 2
• Do not use lindane 1% due to severe safety concerns including seizure risk in children 1, 2
• Do not use oral ivermectin in children under 15 kg due to blood-brain barrier penetration risk 1
• Do not spray or fog the home with insecticides—this is not recommended 5
• Most "resistance" is actually due to improper application technique, not true resistance 1, 2

School Exclusion

The child can return to kindergarten after the first treatment application—no need to wait for complete nit removal or the second treatment dose, though specific school policies may vary 1, 2