How does transmission occur?
Due to the short time period that head lice can survive off the head, transmission may occur most commonly with head-to-head contact, which should be avoided. To further reduce potential for transmission, discourage sharing of combs, brushes, headbands, barrettes, pillows, hats, scarves, coats, backpacks, or other objects that may come in contact with the head. Where possible, place hats, scarves, and coats on hooks or in separate lockers or cubbies to avoid contact. If hooks are shared or clustered, have children place their coats and hats in sealed plastic bags, especially if head lice are present.
Manual removal of nits close to the head is always recommended. Fine-toothed nit combs are helpful. Combing and brushing hair damages lice and eggs significantly. Use of a hair dryer further injures adults, nymphs, and nits.
Manual Removal Steps
- Comb and divide hair into sections, use a metal fine toothed louse comb to remove nits and lice. After combing each section, dip the comb in a container of hot soapy water to remove lice and nits.
- Repeat until all the sections of hair have been systematically combed.
- Clean nit removal comb, clips, brushes, headphones, hats, and other items with hot soapy water.
Removal Aid Details
Unfortunately, no independent studies indicate the benefits of nit removal aids or occlusive substances including petrolatum shampoos. Other occlusive substances have been suggested, such as mayonnaise, tub margarine, herbal oils, and olive oil, but benefits have not been demonstrated.
Head lice shampoos contain insecticides and, if they are not used properly, can be very hazardous. Most treatments for lice are shampoos left on the head for no more than 10 minutes. Most will not kill eggs, so a second treatment is often necessary.
Removing nits close to the head is usually included in the treatment instructions. Most products warn against using the products on broken skin, which is practically impossible given that lice-related itching usually leads to scratching, oozing, and inflammation of the scalp. In this case, use of these products is not recommended.
If repeated treatments fail, some physicians will prescribe higher levels of permethrin (5%), Lindane or malathion, or even scabies treatments (e.g., crotamiton, sulfamethoxazole, trimethoprim, ivermectin). These may be extremely hazardous to children, despite being FDA approved.
Ulesfia (benzyl alcohol) is a relatively new prescriptive treatment for head lice on children 6 months or older. Risks are minimal compared to some of the alternatives, and the product has proven to be extremely effective.
When using a head lice shampoo, minimize body exposure by confining the insecticide to the head hair. Wash the infested person’s hair in a basin or sink so insecticide residues do not reach other parts of the body. The person applying the treatment should wear rubber gloves. Never apply an insecticide to anyone who has open cuts, scratches, or inflammations, and never use these materials on infants without consulting a doctor. In all cases, follow label directions completely and carefully.
With pyrethrin and permethrin shampoos, lice should die within 10 to 30 minutes after treatment. If you find live lice after 30 minutes, resistance may be occurring, and you should discontinue use of that product.
Never resort to dangerous practices such as applying general-use insecticides or materials such as kerosene. Special combs are needed for lice removal and will be effective in eradicating head lice infestations only if used diligently each day for up to two weeks. Combing is critical to controlling head lice because 20 to 30 percent of lice can still be alive after shampooing.
What needs to be done in the home?
Once an infestation is detected, all clothes should be washed in hot soapy water. Pillowcases, sheets, blankets, and other bedding material should also be washed and placed in the clothes dryer on the high-heat cycle to kill the lice and their eggs. Any non-washable items should be dry cleaned or sealed in plastic bags and placed in the freezer at 50 degrees F or lower for 10 hours or more. Vacuuming the home will remove shed hair and nits.
Continue weekly head checks of the whole family.
