Head Louse Description
The head louse is grey in color but does appear to take on the color of its human hosts' hair color. The louse is about 1/16" to 1/8" long, with the male being slightly smaller than the female. The body shape is ovular and flattened. Head lice have hook like claws at the end of each of their six legs to help them grasp hair.
Head Louse Biology
Female head lice lay about 7-12 eggs per day. The eggs of head lice are called nits. Nits are about 1/16" long, oval and white in color. Nits can be found attached to the hair shaft near the scalp of the host. Under optimal conditions eggs will hatch in 7-11 days. After hatching, the louse will go through three nymph stages before becoming a sexually mature adult. This gradual metamorphosis takes about 10-12 days.
Frequently asked questions
Q) Should I spray a residual insecticide around my house for head lice?
A) The answer to this question is NO. There is no reason to spray a residual insecticide around your home to treat for head lice. The adult head louse cannot live more than one or two days with out a blood meal. Nits cannot hatch if they are not on a human host, because their temperature cannot be maintained properly and the nit will not be viable.
Q) What should I do to treat my home for head lice?
A) Clothing, pillows, blankets and sheets should all be washed in hot soapy water and dried for at least 30-40 minutes on high heat in the dryer. Non washable items (stuffed animals, dry clean only clothing...) should be put in the dryer on high heat for at least 30 minutes. Any other items should be sealed in bag for at least 7-14 days.
Carpets and other flooring should be thoroughly vacuumed and the vacuum bag sealed in a plastic bag and thrown away. Furniture can be sprayed with Sterifab. Sterifab is an alcohol based product that includes a synthetic pyrethroid that is safe to spray on furniture and mattresses. Sterifab dries in about 20 minutes and does not leave any residual on the surface that is sprayed.