treatment

Last reviewed 01/2018

Treatment is recommended in the presence of a living louse which confirms the active disease. All family members should be investigated for active lice infestation and those infested must be treated simultaneously (1).

Three treatment methods are available for head lice infestations:

• 1. Insecticides
  • there is evidence of widespread malathion and pyrethroid resistance, as well as the emergence of carbaryl resistance in the UK, hence choice of treatment will depend on patterns of regional resistance. Please refer to local guidelines
    • pharmacological treatment of head lice involves the use of one of the following topical pediculicides:
      • malathion
        • should be applied twice, with seven days between applications It is applied to the hair from the roots to the tips, left on the hair and scalp for 12 hours or overnight and then washed out using shampoo (1,7)
      • pyrethroids (permethrin and phenothrin)
      • carbaryl
    • malathion or phenothrin are recommended as first line treatment methods in people who are using insecticides for the first time
  • in cases of treatment failure with one group of insecticide, switching to a different class is recommended (1)
• 2. Wet combing
  • requires a minimum of four sessions spaced over two weeks and should be continued until absence of full grown lice is seen for three consecutive sessions (1)
  • wet-combing with a fine-toothed comb has been proposed as an option as a first-line treatment in response to the increase in pediculicide resistance
• 3. Dimeticone
  • dimeticone lotion applied to dry hair and scalp should be kept on for 8 hours or overnight and repeat after 7days (1,7)
  • Hedrin lotion (4% dimeticone in a silicone solvent) "..seems reasonable to regard dimeticone as a first-line alternative to malathion, permethrin or phenothrin, particularly for parents or patients who do not wish to use conventional insecticides... (2,5) "

Note that an 'old' drug gaining popularity in the treatment of head lice is oral ivermectin (5). At present, the use of ivermectin is not advised in small children (6). Experience of the use of ivermectin in large institutional outbreaks or crusted scabies is likely to encourage the greater use of this oral agent in recalcitrant cases of head lice (5).

In a pregnant or lactating woman wet combing or dimeticone is advised (1).

Response to treatment should be evaluated 2-3 days after completing a course of treatment by detection combing method. The test can be repeated 8-10 days after treatment to detect any louse eggs that have survived (1).

Other agents (7):

• isopropyl myristate and cyclomethicone (Full Marks solution ®)
  • not suitable for children younger than two years of age or for people with skin conditions Should be applied twice, with seven days between applications Is left in place for ten minutes and the hair is then systematically combed with a fine-toothed comb to remove lice and then washed using shampoo to remove the solution
• coconut, anise, and ylang ylang spray (Lyclear Spray Away ®)
  • not suitable for children younger than two years of age, people with skin conditions, or those with asthma Should be applied twice, with seven days between applications. The spray is left in place for 15 minutes. The hair is then washed using shampoo to remove the spray, and then systematically combed with a fine-toothed comb to remove lice

The summary of product characteristics must be consulted before prescribing any of the drugs mentioned.

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.
• 7. Primary Care Dermatological Society. Head lice (Accessed 29/7/14)