Head Lice Life Cycle

Head lice are tiny little insects that take up residence on a persons head. While they aren't dangerous and do not play a role in the spread of disease, their presence is socially embarrassing and can affect a person psychologically.

Life Cycle of Head Lice
The head lice life cycle progresses in three stages: nit, nymph and adult. Like many other forms of life, the first stage of existence of a head louse is as an egg, called a nit. An adult female lays the egg at the base of a strand of hair, where it remains attached by an adhesive substance. The eggs are laid with proximity to the scalp as the heat it generates is needed for incubation. The nits are approximately 0.8mm by 0.3mm in dimension, oval in shape and posses a color between white and yellow. On an average, they hatch 6 to 9 days after being laid.

The next stage in the head lice life cycle is when the egg hatches and out comes the nymph. It shares the appearance of a grown louse but is only smaller in size. Nymphs are usually as small as a pinhead and have a yellow to rust-color. The shell it emerges from turns yellow while remaining attached to the strand of hair. As the nymph grows, it sheds its exoskeleton 3 times before attaining adulthood. The nymphs wander at the neckline and behind the ears while remaining close to the scalp. They enter adulthood in about 7 days time.

The adult stage in the head lice life cycle is marked with a 5 times a day feeding pattern. It will do this by penetrating the skin using its claws and sucking out blood. Without these regular meals, an adult louse will die within a day or two. Post feeding, the lice take on a rust color, though otherwise they appear grayish white. Adult lice are usually the size of a sesame seed, with females being larger. They have 6 legs with sharp claws used to maintain a firm grip on the strands of hair. Nestled safely on a person's head, they can live for up to 30 days. During this time, the females can and may lay up to 8 nits per day.

Symptoms and Treatment of Head Lice
The first and foremost sign of head lice infestation is itching. Upon checking, one can spot these tiny insects moving about in a person's hair. They can also cause the lymph nodes in the back and front of the neck to swell. People usually contract head lice from a person who already has an infestation. This may happen upon direct contact with the hair or head of that person or even by using their combs / brushes, scarves hats, or coats. However, they can also be picked up from pillows, towels, beds and stuffed animals. Read more on symptoms of head lice.

There are several medications for head lice treatment. Called pediculicides, most have to be applied directly to the scalp and hair and rinsed out after 10 minutes for them to work. These medications effectively kill nymphs and adult lice but fail to destroy nits. However, the nits can be dealt with by applying a second round of the medication after 7 to 10 days, by which time they would have hatched. Nits can also be removed using a fine tooth comb. Remember to exercise caution while using these toxic pediculicides. More on

• Head Lice Treatment.
  
• Getting Rid of Head Lice

Understanding the head lice life cycle puts one in a better position to treat an infestation. If one child or family member has a case of head lice, all other members must be checked for lice.