Lice continue to be a public health problem in 20th century Europe. They are relatively small insects, and often difficult to distinguish. With the return to school they represent one of the main problems of parents, since contagion is very easy. How can they be prevented? Here we tell it.
These insects feed on human blood. Specifically, the egg phase is known as ‘nits’. The louse infests the hair, a female can deposit up to 300 eggs, along with a substance that acts by sticking them to the root, making it very difficult for them to come off. “Nits fluoresce in ultraviolet light, hatch after 5-10 days, giving rise to larvae that mature in a couple of weeks. They live by digesting the blood they suck, making many bites at very short intervals throughout the day “, they point out.
From the Spanish Association of Primary Care Pediatrics (AEPAP) they maintain that, unlike dandruff that comes off easily, the nit is strongly attached, and to detach it they emphasize that you have to grab it between the nail and the fingertips, and pull her hair up.
“They put them very close to the skin because they need heat to incubate. The louse hatches after about 9 days, but the nit shell will still be attached. Considering hair growth, nits located more than 1 centimeter from the skin are usually empty. The newly hatched louse (called a ‘nymph’) measures almost 1 millimeter. The adult lice reach 3 or 4 millimeters, and have a darker brown color than the nymphs,” he describes.
Tips to eradicate and prevent them
Although it depends on how they are installed on the head, their removal will take more or less time, the Spanish Academy of Dermatology and Venerology celebrates that today chemical pediculicidal treatments are “quite effective” and have high rates of removal, both lice like nits.
“Even so, no treatment eliminates them 100% and a second treatment must be performed after 7-10 days. You must strictly follow the instructions for applying the product and keep in mind that the cream or lotion presentations are more effective than in shampoo,” he adds.
Likewise, it stands out that, of the different products marketed in Spain, ‘pyrethrins’ and, in particular, ‘permethrin’ are considered first choice. “But all of them must be complemented with the subsequent removal of lice and nits, which have been killed or damaged, with a suitable nit comb (metallic with cylindrical spikes less than 0.2 mm apart and blunt tip), which improves the outcome of the treatment,” he points out.
In order to prevent lice resistance to treatments, it is recommended never to use these products as preventives, to change the substance if the treatment fails after 3 applications, and in those patients with many episodes to rotate the different treatments. “In resistant cases or massive infestations there are alternatives such as Ivermectin or Cotrimoxazole, which are prescribed by a doctor,” the AEDV adds.
About the natural treatments that have been used throughout life as the typical tea tree (which you can get at ), coconut oil or Vaseline, for example, he mentions that they do suffocate the lice but they are less effective than the classic chemical products.
As for the vinegare, used especially by our grandmothers, AEDV highlights that its direct action against lice requires high concentrations, but it has limited efficacy, as well as the possibility of irritation. “However, dilutions of two parts of water and one part of vinegar do help to facilitate the detachment of nits and may be useful for this purpose,” he warns.
Regarding the use of preventive products, the AEDV says that natural repellents such as the essence of the tea tree or citronella oil, for example, are usually recommended, although there are not enough studies to support their effectiveness. “The most effective form of prevention is periodic review with a nit comb, which will allow early diagnosis,” he points out.
In fact, he considers that it should be established as a regular method at these ages, and especially in those minors who are among these risk environments. “Check-ups are recommended every 7-10 days, and it is advisable to do it on Fridays so that in case of seeing parasites, they can be treated during the weekend and return to school without infection. Although the difficulties involved must be recognized, as it is a long and thorough. However, it should be integrated as part of the grooming routine,” he adds.
For children under 2 years of age, the AEPAP emphasizes that the best treatment consists of cutting their hair, the shorter the better, as well as removing lice and nits by hand. “If you don’t want to cut his hair, buy a nit comb and softening cream and pass it, every 3 days, until in 3 successive combs you do not remove any lice. Between combing, hand remove any nits you see. If you can’t eradicate them like this, you could use an insecticide called permethrin, but only for older than 2 months,” she says.
If there is a contagion by lice, the AEPAP says that calmly the day after having carried out a correct treatment with permethrin, malathion, pyrethrins with synergizers, or dimethicone, even if there are nits, minors can return to school.
To prevent an infestation, consider that the risk of contagion is lower by collecting the hair if it is long (pigtails, bows), or covering it (scarves). “Short hair not only prevents infection, but also makes any treatment much easier. Brushes or combs, hats or headbands should not be shared,” she clarifies.
Other measures like wash towels, hats, sheets, or pillow covers at 60 degrees, for example, as well as vacuuming fabrics in contact with the head that are not washable, and storing non-washable objects in a plastic bag for 2 weeks (lifetime of a nit), can be carried out; but not obsessively because they are surely unnecessary.