The Prevention and Treatment of Head Lice in Children

Suzanne Albrecht, PharmD, MSLIS

US Pharmacist

Treatment

The optimal treatment would be readily available, easy to use, effective and safe, affordable, and non–resistance-promoting.^[2] Prophylactic treatment is not recommended.^[3] OTC and prescription-only medications are approved for use in the U.S.^[2] These products, which are pediculicidal (kills live lice only) or ovicidal (kills lice and eggs), act either on the louse's nervous system or as occlusive agents.^[6]

Many reports exist of resistance to the OTC agents; however, in the case of treatment failure, improper use by the patient should be suspected first. Some experts recommend removing nits with a nit comb after treatment.^[2]

Based on life cycle, pediculicidal agents that act on the nervous system ideally should be applied twice. The first application kills all hatched lice. Nine days later (rather than 7 days, as some manufacturers recommend), a second application kills all newly hatched eggs not killed with the first application. If the second application is done on day 7, some eggs laid just before the first application have not yet hatched, based on the average hatching time of 8.5 days.^[4]

1 2 3 4 5 6 7 8 9 10 11 12

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Table 1. Medication Application Instructions
Permethrin
Shampoo hair with nonconditioning shampoo, then towel it dry. Apply to damp hair and leave on for 10 minutes. Rinse off with warm water. Repeat if live lice are seen after 7–10 days.
Pyrethrins With PBO
Apply to dry hair. Rinse out after 10 minutes. Repeat after 9 days.
Malathion
Apply an amount sufficient to entirely cover dry hair and scalp (keep eyes tightly shut). Allow hair to air dry. Hair should remain uncovered after application. Shampoo hair after 8–12 hours. Use a nit comb after shampooing to remove lice and eggs. Repeat if live lice are seen after 7–9 days.
Benzyl Alcohol
Apply to dry hair, using enough to completely saturate hair and scalp.^a Rinse off with water after 10 minutes. Repeat in 7 days (although waiting until day 9 may be more effective).
Spinosad
Apply first to dry scalp, then to dry hair in amount sufficient to cover entirely. Apply up to 120 mL (depending upon hair length). Leave on for 10 minutes. Using warm water, thoroughly rinse hair and scalp. Repeat if lice are seen after 7 days.
Ivermectin
Apply to dry hair in amount sufficient to coat hair and scalp (up to 1 tube). Leave on for 10 minutes. Rinse off with water.

^aFor hair ≤4" long, 1 bottle will suffice; hair up to 16" long may require up to 3 bottles; hair longer than 22" may require up to 6 bottles.
PBO: piperonyl butoxide.
Source: References 2, 7, 10, 12, 17.

Table 2. Treatment Counseling Points
Shake bottle before using and wash hands after applying. Use warm (not hot) water to rinse off products over a sink (rather than in a bathtub or shower). This limits systemic exposure. Be sure to treat all of the hair and scalp. Pay close attention to the back of the neck and behind the ears. Check all household members, and treat those with live lice or nits occurring ≤1 cm from the scalp. Family members who share a bed with the patient should be treated. Pediculicidal agents ideally involve 2 treatments administered 9 days apart. Using a nit comb after treatment may increase the likelihood of complete eradication. Itching/burning sensations do not necessarily mean that treatment has failed. Topical corticosteroids and/or antihistamines may alleviate these adverse effects. Although indirect transmission is rare, personal items may be washed at 130°F. Items that cannot be washed (e.g., furniture, car seats, carpet) should be thoroughly vacuumed. Since nits need warmth to hatch, pediculicide spray is not recommended for personal items. Although probably unnecessary, large items (e.g., pillows, comforters) may be bagged in plastic for 2 weeks.

Source: References 2, 4, 10, 12.

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The Prevention and Treatment of Head Lice in Children

Treatment

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