They're as small as a pencil lead yet just mentioning them makes people start to itch. What are they' Head lice!

With school starting, these little pests will be moving through school age heads with a vengeance. Students, parents and teachers should know how head lice are transmitted and how to recognize and treat infestations.

Of the three types of lice -- head, body and pubic -- head lice are the most common in the United States and are most prevalent in school age children. Contrary to popular belief, infestations are not related to poor hygiene or lower socio-economic status. Head lice are equal opportunity nuisance pests that happily use any human as a host. Their presence is more an indicator of interpersonal contact than lack of cleanliness.

Head lice are wingless insects, about one-tenth to one-eighth of an inch long, with piercing and sucking mouthparts used for feeding on human blood. They are flat in shape, white to gray in color and have short legs with large claws which grasp and hold onto hair. They are most common in school age kids grades K-8 due to head to head contact during play and sharing of personal items such as combs, brushes, hats, hairbows, etc. They can also be transmitted through close placement of coats, scarves and other items in lockers, coat racks, etc. Human head lice cannot be acquired from animals or birds and they do not transmit diseases.

The lice burrow themselves onto the scalp usually behind the ears and at the back of the head. They may also be found in the eyebrows or beard. The female lice feed on human blood about every four hours and then produce one egg. Approximately six eggs are produced each day. The lice glue the eggs (or nits) to the hair shaft about one-fourth inch from the scalp. The eggs hatch in about one week and feed within 24 hours. Mature lice live approximately 30 days, during which time the females can lay 50-150 eggs so that a single infestation may involve hundreds of nits.

While there are no outward symptoms of lice infestation, parents and teachers should be aware of children with persistent scratching of the scalp. Identification of lice is enhanced with a magnifying glass and sufficient light to view the scalp. Closer inspection will reveal the small, silvery nits attached to the hairs. There may also be infected scratch marks or a rash-like appearance where the adult lice are attached.

It is not usually necessary to visit a doctor unless secondary infection has occurred due to scratching. There are numerous over-the-counter lice treatments (or pediculocides) available; your pharmacist can recommend one for you if you need assistance. These products are pesticides approved for human use so it is important to use them exactly as directed on the package. Generally, an initial treatment is followed by an additional treatment in about 7-10 days to kill any newly hatched lice. The cement holding the nit to the hair shaft is not dissolved with the treatment so the nits need to be removed using the nit comb that comes with the package. Removing nits is easier if the hair is wet and if a conditioner has been used on the hair first. Clothing should be changed after the treatment and nit removal is through.

Wash clothing, bedding, towels and other items that were in contact with the infected person, in hot water and dry in a hot dryer about 20-30 minutes. Items may also be dry cleaned or sealed in a plastic bag for 30 days. Soak combs and brushes in very hot water or treatment shampoo for 10 minutes. You may also vacuum carpets, upholsteryand mattresses used by the affected individual, though this is not necessary.

To help prevent lice infestation, discourage children from sharing coats and personal items with other children. Ideally, separate hooks at least 12 inches apart; cubbies or lockers should be assigned to each child. If this is not possible, have children hang coats on the back of their seats and keep coats and scarves at the child's desk. If scratching is noticed, check the child right away as well as family members for the presence of lice.

For more information on lice, call Preventive Medicine at Fox Army Health Center at 955-8888, ext. 1026.

Editor's note: Cherie Miller is the environmental health consultant at Preventive Medicine, Fox Army Health Center. For more information, she may be reached at 955-8888, ext. 1441 or at