Doc: Mechanical removal of lice requires time, patience

Dear Dr. Roach: I am an adult woman who somehow has gotten head lice. This has been a traumatic adventure, since I have been unsuccessful in ridding myself of it — and it has been a little over a month of diligent trying.

I used a natural remedy made from chrysanthemums; it didn’t work. Now I am using kosher salt dissolved in water, with a vinegar rinse. I then wash, condition and comb out nits.

I am vacuuming my furniture and floors daily. I am washing my clothes in hot water, and I change my sheets and towels every other day after treatment.

I feel like I am making headway, but I am afraid that I will never be lice-free. I do not want to use RID or Nix, as they are pesticides. I read that today’s lice strains are resistant anyway. What works?

K.D.

Dear K.D.: Head lice (Pediculosis capitis) is a problem with many different possible solutions, only a few of which have been proven to work. Pyrethrin, the chrysanthemum-based medicine you tried, is effective in many people. There is a synthetic version available, permethrin (Elemite or Nix), but you are correct that there is resistance to it in many areas. To be effective, mechanical removal requires time and patience — 15 to 30 minutes a day of wet combing is the minimum recommended, and people with longer or thicker hair may need much more. You need to have a specially made, fine-tooth comb used specifically for lice removal.

Unfortunately, mechanical removal is not 100 percent effective in the real world: Studies in the U.K. showed 38 to 57 percent effectiveness. This probably reflects poor technique and lack of patience.

Given the failure of the chrysanthemum extract treatment you tried, I probably would recommend the pesticide malathion (Ovide is the brand name), but benzyl alcohol in mineral oil (Ulesfia or Zilactin) would be an alternative for those who want to avoid pesticides; it works by asphyxiating the lice.

Both of these treatments are about 80 percent effective. Both of these treatments can be irritating to the scalp and eyes, and malathion is potentially flammable. Resistant cases may require oral medication (but I’ve never had to prescribe that).

I prefer mechanical removal, as there are possible side effects of any chemical treatment for lice. These are more likely in children (and especially infants), as their scalp can absorb chemicals more readily than adults’.

Email questions to ToYourGoodHealth@med.cornell.edu.