Oral Co-trimoxazole works for persisting head lice

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Goodfellow Gems

"Oral Co-trimoxazole works for persisting head lice"

I recall a mother with a child around 5 years of age with persisting head lice. The child could not stop scratching her scalp, which had become excoriated. The mother was angry and upset at the failure of topical and mechanical treatments. I was aware of the 2001 paper and gave her a 10 day course of oral co-trimoxazole 10mg/kg/day in two doses. The mother and daughter returned a few weeks later and both were delighted with the lice free head of hair and the healed scalp.

In the trial they found that permethrin 1% (note that in NZ the dose is 5%) had a 72% success rate at 4 weeks while permethrin combined with co-trimoxazole had a success rate of 93%. 1 The bacteria in the gut of the lice, are killed when the lice feed on the blood of a person taking this antibiotic-the lice then die. Co-trimoxazole should only be used after multiple treatment failures.

  1. http://www.ncbi.nlm.nih.gov/pubmed/11230611

Gems are chosen by the Goodfellow director Dr. Bruce Arroll to be either practice changing or practice maintaining. The information is educational and not clinical advice.

As published in NZ Doctor 01/04/2015