Treating crabs involves applying over-the-counter shampoo or cream rinse containing permethrin or pyrethrins. For resistant cases, topical malathion (a highly effective prescription medication approved only for patients older than 6 years) or lindane may be used.
Lindane, a second line treatment, should only be prescribed to patients who are unable to take other medications or who have not responded to them. According to the Food and Drug Administration’s warning, lindane can rarely cause serious side effects, including seizure and death. Those especially susceptible are infants, the elderly, children and adults weighing under 110 lbs, and individuals with other skin conditions. Lindane is a toxin and should not be overused. Patients are given small amounts (1-2 oz) of the shampoo or lotion and instructed to apply a very thin layer and not to reapply. For more information, visit the Center for Drug Evaluation and Research website .
- Wash the infested area, and then towel dry.
- Thoroughly saturate hair with lice medication. If using permethrin or pyrethrins, leave medication on for 10 minutes. (If using lindane, leave on for only four minutes.)
- Thoroughly rinse off medication with water. Dry off with a clean towel.
- Following treatment, most lice eggs will still be attached to hair shafts. You can remove them with your fingernails or tweezers.
- Put on clean underwear and clothing after treatment.
- If you have lice in your eyebrows, you may be directed to coat your eyebrows thoroughly with petroleum jelly.
- To kill any lice and nits that may be left on clothing or bedding, wash those items used during the 2-3 days before treatment. Use the hot water cycle (130°F) of the washing machine. Use the hot cycle of the dryer for at least 20 minutes to dry clothes.
- Dry clean clothing that is not washable.
- Avoid any sexual partners until they have been treated.
- If necessary, retreat in 7 to 10 days.