How to Identify Different Types of Lice and Nits

School nurses and public health clinic nurses may see “pediculosis,” an infestation with different types of human lice, from time to time.

Of late, this has been a more frequent occurrence. The general public may not hear so much about pediculosis, for those affected are reluctant to spread this information.

Human lice are a group of insect parasites which live on the bodies of their victims. They are known as sucking lice and depend on the blood for nourishment. The warm human body also provides warmth and moisture.

There are several varieties of human lice, called pediculosa, all parasites that suck human blood. The three types of human lice are: Pedicuius humanus capites, the head louse; Pediculus humanus humanus, the body louse; and the crab or pubic louse, Pthirus pubis.

Body Lice 

Body lice are hard lo find on the skin, because when not feeding they hide and plant their eggs in the folds or seams of clothing. Body lice live in the seams and linings of clothing, blankets, and sheets and move to the body when feeding.

These are the lice which carry disease – typhoid, trench and relapsing fever, all serious diseases. The body louse, which is generally limited to those who don’t bathe frequently, can transmit certain diseases, but body lice are rare in the U.S., and appear mostly in areas where no modern hygiene and sanitation exist. Of the three kinds of human lice, only the body louse has been implicated as vector a carrier of louse-borne disease, like relapsing fever and epidemic typhus in times past.

Pubic Lice 

The head and body louse have almost the same physical size and shape, but the crab louse has a rounder body and its second and third pairs of legs are larger than the first pair near its head. Pubic lice are found among coarse hairs around the rectal area and sex organs, but occasionally migrate to the eyebrows, eyelashes, head or over the body if the person is unusually hairy.

Crab lice live on the hairy parts of the body, usually in the pubic and perinatal regions. Since prepubertal children have no hair in these areas, crab lice are uncommon before adolescence.

Pubic lice are popularly called “crabs” because they look so much like crabs: They are fatter than body or head lice, having almost same width as length, and have six legs and claws curve outward. These lice can be acquired by sitting on a toilet seat shortly after someone else who has them. But contrary to the scribbles on washroom walls, “crabs” only crawl, they do not jump.

If you suspect lice, but cannot find them, your doctor can help find them by using a special ulraviolet fluorescent lamp called a black light.

Signs and Symptoms of Different Lice

The first symptom of lice usually is an intense itchy swelling. Children scratch so hard they make bloody red marks, which can become infected.

Pyoderma: In other cases, the first sign may be pyoderma, a type of ulcer with pus. Pubic lice may cause flat, sky-blue boils on the lower abdomen or between the thighs.

Animal Lice  

Three types of lice infecting humans live only on humans. Animal lice, on the other hand, can’t maintain themselves on humans. And, it’s possible for a person to have more than one type of lice.  Do head and pubic lice carry disease? No. There has been no evidence to indicate that head and pubic lice carry disease, but their presence causes considerable mental anguish to parents.