Pediculosis

Symptoms

Itchings, in particular around the Ear S, like near the Nape of the neck (but in 40 to 50% of the cases, there is no prurit).
Presence of slow; ovals, brown, smooth and brilliant when they are alive, and blanchâtres after the blossoming (3 weeks after the laying), but remaining stuck to the hair. The slow alive ones are located at less than 5 mm of the scalp; beyond they are empty (time between the laying and the blossoming is 10 days to the maximum).
Presence of lice alive, mobile, of color gray-beige, but difficult to see.

Biology

The lice of head live 6 to 8 weeks. Their females lay 4 to 10 eggs (or Lente S) per day during 3 to 4 weeks (100 to 200 eggs laid by female). After 7 to 10 days spent firmly fixed on the hair or a hair, the louse leaves slow in the form of Larve, which will become adult in less than 15 days. The lice thus have an important capacity of reproduction.

The louse of the man generally settles in the hair. The adult louse measures between 2 and 4 Misters It obstructs his host by the itching which it causes (answer of the immune system) and sometimes by superinfections (Impétigo). It lays eggs in quantity which will become in their turn of the “harmful” adults including laying females. In contact with another hair, for example in contact with another child during a play or of a brawl, or during exchanges of clothes, muffler, bonnets or caps, the louse will be able to change host and its colony will extend thus from people with people.

Prevention

Prevention is better than cure: it is advised to observe the hair of the children regularly and/or to pass them to the comb to louse to detect the possible appearance of these parasites. The appearance of lice in a school does not imply a defect of hygiene; the lice often reappear at the beginning of school year, with the return of the holidays (September, November October, mid-December).

To the difference of the chip S, the lice do not jump. They do not fly either. They move only while rempant or via clothing or hair infested. To avoid the direct contacts strongly limits the extension risk. It is thus preferable to announce to its entourage and the school the presence of lice in order to limit the contacts, in particular between chevelures.

It seems that the contagion by clothing and brushes is not the principal vector. Indeed P. capitis cannot survive a long time out of the scalp. He dies dehydrated after 4 a.m. in a dry air and with the sun, and after 36 hours to the maximum (if the air is wet and tepid). There is not either a proof of contagion by water (swimming pools…).

To avoid the appearance and the diffusion of lice resistant to one or more insecticides, and of useless irritations of the scalp, it is necessary to avoid any useless chemical treatment and to be certain presence of lice or slow alive. The more so as the pesticides used against the lice are pain-killers, neither for the child, nor for the environment (strong remanence and toxicity of the Lindane which is interdict for the majority of its former practices and dérogatoirement authorized against the lice/toxicity of the Malathion, of the Perméthrine, of the Méthoprène, D Phénotrine, even of the Pyrèthre S or Pyréthrinoïde S of synthesis for the environment. These products massively used in a city or a district at the time of the epidemics of pediculosis, can moreover contaminate sewers, clarification sludge, etc, via the rinsings of shampoos). In the poor countries, the rinsing is done often outside, on the ground. Lastly, the insecticides are not used in prevention because of absence of shown residual activity.

Treatment

To fight against the lice implies three parallel steps:

to eliminate the adult lice,
to eliminate the Slow S (because they will become lice which will lay the slow ones, etc)
to limit the transmission of the lice of a person to another.

The three principal methods of elimination of the lice and slow are:

the total shaving of cranium, by throwing hair, lice and slow with the dustbin, before careful washing of clothing and bed linens. This method very effective, most radical, has like disadvantage of obliging the victim of the lice to carry in public a head bald person, which can be difficult to live, for the children in particular.

manual the method known as “delousing” consists with carefully combing the hair (30 minutes), in way repeated (3 times then 2 times per day), during 3 weeks, on wet hair, preferably with a special comb. This method is recommended in Great Britain, in the children of less than 6 months, during the pregnancy and at the asthmatic patients.

the chemical method consists in washing the hair with a Shampooing, a lotion or an aerosol Insecticide (Adulticide, i.e. killing the adult insect), and/or Ovicide (killing egg), like traditional the lotion and shampoo Marie Rose . The Butoxyde of pipéronyle is a synergistic which improves the effectiveness of derived from the pyrèthres or pyrethrinoid. The Lindane does not have any more its place in the treatment against the lice, in particular because of undesirable effects, sometimes serious, especially in the child. According to WHO the lindane is contra-indicated before the 10 years age and the pregnancy.

The insecticides in solution, lotion or cream are preferable with the sprays and powders which are likely to be inhaled or to touch the mucous membranes and the eye, with a case risk of Asthme and Bronchite asthmatiforme. The shampoos and the powders are less effective according to the experts questioned by the French Ministry of health. A shampoo not-insecticide must follow the treatment to clean the hair and the scalp.

The most coherent choice is to apply to dry hair a lotion containing pyrethrin, to let act 30 minutes (15 mn before the 2 years age), then to rinse and comb with a comb to lice. The procedure is to be renewed one week later. In the event of failure the malathion is an alternative

Random links: