( Originally Published 1927 )
The lice which may attack the skin surface are of three different varieties: those found on the scalp, those invading the body, and those occupying the region of the genitals. As each type is more or less limited to its special location, three different forms of this affection will be considered.
Head Lousiness (Pediculosis capitis).
Description.—In head lousiness, the nits or eggs (ova) are always present and are attached to the hair but cannot be brushed off, because of a skin-like body which binds the nits to the hair. By this feature, it is possible to tell the difference between nits and scales, for scales can be brushed off.
The presence of the lice causes severe itching which is followed by scratching and the formation of crusts. In neglected cases, the crusts may mat the hair together and when these crusts decompose, a foul odor results. At times, the glands in the back part of the neck may be swollen and even become abscessed. Where lousiness of the scalp has long been present, the neck and even the face may also become the seat of eruptions. While head lice usually limit their activity to the scalp, they may also attack a long and poorly kept beard.
Contagiousness and Transmissibility.—Head lice are more common among girls, and more frequent in children than in adults. Uncleanliness and neglect of the scalp favor this condition. The disease is contracted through close contact with persons having lice or perhaps through wearing infected caps or other headgear. Infection with head lice is extremely common among the poor children of school age. The Negroes seem to be less liable to this infection than whites.
Suggestions for Prevention and Treatment.—Probably the most efficient remedy against head lice is raw petroleum. It is safest to use it weakened with an equal amount of olive oil. This preparation should be applied to the scalp at night, followed by a shampoo in the morning with ordinary soap and water, or with tincture of green soap and water. This is to be repeated for several nights. Removal of the nits can be hastened by frequent application of a solution of bicarbonate of soda or vinegar. Use of a fine-toothed comb also assists materially in the removal of the nits. It is rarely necessary to sacrifice the hair of women so infected, although this may be done in children. It must be remembered that much time and' effort are necessary to cure lice infection of the scalp. Frequent inspection of the scalp and hair is the best preventive for this condition.
Lice Infection of the Body (Pediculosis corporis). — Description. — In this variety, the lice live in the seams of the underclothing and there deposit their ova (eggs), the body being at-tacked only when the parasites are in need of nourishment. They obtain the blood by inserting their suckers into the skin, these situations being marked by small bloody spots. Presence of the parasites causes itching, followed by intense scratching. The scratch marks are in the form of lines, especially numerous over the small of the back and between the shoulder blades. In long-standing cases, the color of the skin may become brownish.
Contagion and Transmission.—Infection with body lice occurs principally among the poorer classes and attacks persons of middle and advanced life. It is at times seen among the better class of persons, usually among those who are older. It is rare among children and young people.
Suggestions for Prevention and Treatment.—In the treatment of body lice, it is most important to fumigate the clothes and bed linen. A soap and water bath, followed by the application of olive oil containing three to five drops of carbolic acid to the ounce, relieves the itching.
Infection with Crab Lice (Pediculosis pubis).—Description.—In this form of lice infection, the parasites stick to the hair with their beads buried in the mouths of the hair sacs. The nits are attached to the hair in the same manner as in the head-lice infection. Itching about the genitals is usually most severe, so that scratch marks and bloody points are visible. While the parasites are usually found about the genital region, the armpit area, the beard, the eyebrows and eyelashes may also be invaded.
Transmission.—Infection with crab lice is almost exclusively seen among adults and is usually contracted during sexual intercourse.
Suggestions for Treatment.—When treating infection with crab lice, it is advisable to wash the affected part frequently with soap and water. Vinegar and soda solutions are useful for the removal of the nits. Patent and drug store preparations should be avoided, and only remedies pre-scribed by a physician should be applied. The commonly used blue ointment may cause an irritation of the skin, more troublesome and annoying than the original infection.
Description of the Parasites.—The head louse is usually of grayish color. Its head has two hairy feelers and two eyes. The chest is rather narrow and the stomach is divided into seven parts. The male is scarcer and smaller than the female and measures from one five-hundredth to about one-tenth of an inch in length and about one-half that size in breadth.
The body louse looks like the head louse, excepting that it is larger. This varies in color from a dirty white to a light gray, but when swelled with blood it is dull-reddish or purplish.
The louse which attacks the genital region is the smallest of the three and is about as long as it is broad. Its shape has been compared to that of a violin. It is provided with six stout legs, the second and third pair being most powerful and showing large hooks. It is called the "crab louse." This "crab louse" is provided at its sides with eight short, conelike feet ending in bristles.
The female lays the eggs, called the "nits." Upon the scalp these are deposited along the hair and are gradually removed from the scalp as the hair grows. The youngest are those nearest the scalp. The nits are whitish or grayish in color, of oval shape and are so attached to the hair, by a sheath, that the hair is completely encircled. It is stated that one female head louse can lay fifty eggs in six days and in eight weeks may have a family of five thousand lice. The nits of the body lice are deposited in the clothing and each female of this variety can lay as many as fifty eggs. The female crab louse can lay only twenty eggs.