Lice: Symptoms, Prevention & Treatment

Lice are parasites that live on people’s heads and are very common. They predominantly affect children between the ages of 3 and 10 and their relatives. They are very easily spread. Girls are affected with head lice in greater proportion than children because they have long hair. Lice are tiny wingless insects that live on human scalps and feed exclusively on blood. Lice can be found anywhere in the world, but they prefer cooler climates because it takes them longer to reproduce at higher temperatures.

Lice do not transfer diseases and will not live off any other host than humans, making louse infestations a purely cosmetic issue. Lice treatment is usually done with special shampoo containing insecticide or pyrethrin-based compounds, which kill the louse’s nervous system by blocking its ability to breathe.


Characteristics of Lice

Lice do not jump or fly because they do not have wings, but they move very fast. Its average speed reaches 23 centimeters per minute under normal conditions. They walk through the hair firmly clinging to it with 3 pairs of short legs. The louse has a flattened body and its color is white. Although once the louse is full of blood, its color changes and becomes gray, brown or black.

An adult louse usually measures between 2 and 4 millimeters. Your abdomen is wider than the rest of your body and breathes through holes that can close and become impermeable to water. They have the ability to hold apnea for about five minutes. These openings also have an excretion function. You May Also Like To Read Mite

Its head has short antennas and highly specialized mouthpieces, which allow the head louse to perform perforation and suctioning operations on the blood of its host. Lice are hematophagous insects, a kind of ‘microscopic vampires’, which feed on human blood and are very sybarite. They prefer some people more than others according to the composition of their blood.

Some studies suggest that it is possible that certain foods or medications, which alter the smell or taste of blood can cause rejection. Its diet consists exclusively of the blood of its host. To eat, lice bite 2 to 4 times a day during meals, which last about 30 minutes. Far from their host, head lice can not survive for more than 48 hours, as they starve or dehydrate.

In addition to feeding regularly with blood, they need conditions of climate and humidity necessary for their survival, which is very strict: temperature between 28 and 32 ºC with 70 to 80 percent humidity. The optimum temperature of rapid growth oscillates around 28 ° C. They do not withstand temperatures above 45 ° C.

Below 27 ° C the growth slows down, while below 12 ° C growth and egg-laying stops. In general, they are quite sensitive to the temperature and, in the case of a fever of the host, they can abandon it.


The most common symptom of human pediculosis or lice infestation is pruritus or itching of the scalp. The itching is due to irritation of the skin produced by saliva (which contains an anticoagulant toxin), which the insect deposits in the microgrid of the sting itself.

The itching is due to the irritation of the skin produced by lice saliva (which contains an anticoagulant toxin), which the insect deposits in the microgrid of the sting itself. The bite results in a small reddish-colored papule, which is quite itchy. This irritation, aggravated by scratching, can lead to dermatitis which, in turn, carries a risk of secondary bacterial infection.

Prevention & Treatment

Head lice pass from one head to the other in a very easy way. Therefore, it is necessary to take some appropriate hygiene measures:

  • Comb and brush the hair daily.
  • Frequently check the head, mainly behind the ears and at the nape of the neck.
  • Clean combs and brushes frequently.
  • Do not exchange tools such as combs, caps, rubbers, forks, etc.

The treatment used against lice is the application of pediculicide. The pediculicide has to be applied on dry hair, then proceed to manual removal of lice and nits. Creams and lotions would be more effective than shampoos, which are diluted with water. After letting the product act, you should wash your hair with the usual shampoo, comb it and let it dry in the air.

After applying the pediculicide will proceed to:

  • Rinse with water and vinegar (one part of vinegar and two of water), to favor the elimination of the nits.
  • Do not tumble dry.
  • After rinsing the hair, remove the nuts with your hand or with a comb of very close spikes.
  • The combs should be immersed in a pediculicide for an hour, and all kinds of hair adornments. Clothes, as well as towels, etc., should be washed with warm water.
  • All persons living with the parasitized person should be reviewed and, if appropriate, treated in the same way.

If the treatment has been done correctly, at 24 hours the person stops being infective, although it is necessary to repeat the treatment after 7 days.


To follow the treatments and hygienic measures for a lice infestation, it is advisable to consult the pharmacist, a health educator or the family doctor. They are professionals who can provide summary information in a didactic and simple way. Pediculicides are products of personal hygiene with substances toxic to lice, which act at different levels in their organisms to death. They come in different forms: sprays, shampoos, foams, lotions, etc. In general, it is necessary to cover the area of application in the head of the pediculicide with a cap of showers to improve the result of the pediculicide in the treatments.

As A References: Wikipedia

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