Treating Head Lice Infestation with Malathion

Download PDF version formatted for print

• Steps for treating head lice infestations with malathion
• My child is under 2 years old and has been diagnosed with head lice. Can I treat him or her with prescription or over-the-counter drugs.
• Are treatment failures with malathion common?
• Is a second treatment needed?
• Does malathion kill head lice eggs?
• My child has head lice. I don't. Should I treat myself to prevent being infested?
• Should my pets be treated for head lice?
• Should household sprays be used to kill adult lice?
• Should I have a pest control company spray my house?

Steps for treating head lice infestations with malathion

Malathion (Ovide* lotion) was re-approved by the Food and Drug Administration (FDA) as a prescription drug for the treatment of head lice infestation in the United States. Follow the directions below to treat a head lice-infestation.

Step 1: Treat the person infested with head lice:

1. Before applying malathion lotion, remove all clothing from the waist up.
2. Apply malathion according to label directions, to dry hair until the scalp and hair are wet and thoroughly coated. Leave the medication on the hair for 8-12 hours; allow the hair to dry naturally. Have the person put on clean clothing once medication has been applied.
3. (Consider treating just before bedtime. Once malathion has been applied to the hair and scalp, cover any pillow(s) with a towel to keep medication from staining the pillow.)
4. After 8-12 hours, thoroughly wash hair.
5. A nit (head lice egg) comb should be used to remove lice and nits from the hair. Many flea combs made for cats and dogs are also effective.
6. After treatment, check hair for lice and comb hair with a nit comb to remove nits and lice every 2-3 days. Continue checking for 2-3 weeks until you are sure all lice and nits are gone.
7. If crawling bugs are found 7-10 days after treatment, retreat with the same or different louse medication.

Warnings and Precautions:

1. Malathion may cause stinging, especially if the scalp has open sores from scratching.

2. Malathion is flammable. Keep medication out of the eyes and away from heat sources such as hair dryers, electric curlers, cigarettes, or open flames.

3. Pregnant and nursing mothers should only use malathion after consulting their physician.

Step 2: Treat the household:

Head lice do not live long if they fall off a person. You do not need to spend a lot of time or money on house cleaning activities. Follow these steps to help avoid re-infestation by lice that have recently fallen off the hair or crawled onto clothing or furniture.

1. To kill lice and nits, machine wash all washable clothing and bed linens that the infested person has worn or slept on during the 2 days before treatment. Use the hot water (130°F) cycle. Dry laundry using high heat for at least 20 minutes.
2. Dry clean clothing worn 2 days before treatment if it is not washable, (coats, hats, scarves, etc.) OR store all clothing, stuffed animals, comforters, etc., that cannot be washed or dry cleaned into a plastic bag and seal for 2 weeks.
3. Soak combs and brushes for 1 hour in rubbing alcohol, Lysol* , or wash with soap and hot (130°F) water.
4. Vacuum the floor and furniture. Do not use fumigant sprays; they can be toxic if inhaled or absorbed through the skin.

Step 3: Prevent Reinfestation:

Lice are most commonly spread directly by head-to-head contact and indirectly though sharing contaminated clothing or belongings. Teach your child to avoid playtime and other activities that are likely to spread lice.

• Avoid head-to-head contact common during play at school and at home (slumber parties, sports activities, at camp, on a playground).
• Do not share clothing, such as hats, scarves, coats, sports uniforms, hair ribbons, or barrettes.
• Do not share infested combs, brushes, or towels.
• Do not lie on beds, couches, pillows, carpets, or stuffed animals that have recently been in contact with an infested person.

My child is under 2 years old and has been diagnosed with head lice. Can I treat him or her with prescription or OTC drugs?

For children under 2 years old, remove crawling bugs and nits by hand. If this does not work, ask your child's health care provider for treatment recommendations. The safety of head lice medications has not been tested in children 2 years of age and under.

Are treatment failures with malathion common?

No, however reinfestation is common.

Is a second treatment needed?

Maybe. If crawling lice are still found, a second treatment may be given in 7-9 days. Other family members should be checked for signs of infestation.

Does malathion kill head lice eggs?

No. However, some medication remains on the hair for several days to kill any lice that may hatch after initial treatment.

My child has head lice. I don't. Should I treat myself to prevent being infested?

No, although anyone living with an infested person can get head lice. Check household contacts for lice and nits every 2-3 days. Treat only if crawling lice or nits within a 1/4 inch of the scalp are found.

Should my pets be treated for head lice?

No. Head lice do not live on pets.

Should household sprays be used to kill adult lice?

No. Spraying the house is NOT recommended. Fumigants and room sprays can be toxic if inhaled or absorbed through the skin.

Should I have a pest control company spray my house?

No. Vacuuming floors and furniture is enough to treat the household.

*Use of trade names is for identification purposes only and does not imply endorsement by the Public Health Service or by the U.S. Department of Health and Human Services.

Revised October 19, 2004

Head Lice Infestation

Treating Head Lice Infestation

Body Lice Infestation

Pubic Lice Infestation

Head Lice Infestation

Lice Infestation