recommendations for the application of pediculicides

Last reviewed 01/2018

The following guidelines should be considered when treating head lice pharmacologically:

• lotion preparations should be used and a contact time of 12 hours is recommended (1) - shampoos are not recommended
• the whole family should be treated
• alcoholic preparations should not be used by people with asthma or eczema - alcohol fumes may irritate the airways and irritate the skin
• malathion and permithrin preparations are claimed to confer a residual protective effect against reinfection which lasts up to 6 weeks
• insecticides must be applied to the hair from the roots to the tips and should be left on for 12 hours (or overnight) and then rinse off
• whatever treatment has been administered - there should be a repeat treatment after 7-10 days to kill lice that have hatched from eggs surviving the first treatment (1)
• two to three days after the final application of insecticide familes should undertake combing to check whether or not treatment was successful
• insecticides such as malathion and phenothrin should not be used more than once a week and should not be continued for more than 3 weeks (1)

Dead nits may be removed mechanically with a fine-toothed comb, or alternatively, with vinegar ie. acetic acid 5%, followed by combing. Lindane is no longer recommended.

There is an increasing problem of pediculicide resistance which has made physical treatments such as wet-combing more attractive.

Reference:

• 1. CKS. Safe practical clinical answers. (2007) head lice
• 2. MeReC Bulletin (2008); 18 (4)
• 3. MeReC Bulletin (1999); 10 (5):17-20.
• 4. Prescribers' Journal (1998); 38 (2): 80-6.
• 5. Drug and Therapeutics Bulletin (2007); 45(7):52-5.
• 6. Dermatology in Practice (2002);10(4): 26-29.