He was shown that in UVB, the (cancerous) carcinogenic effectiveness of the solar spectre compounded perfectly with its ryth male effectiveness. In other words, it means that the risk of cancer is proportional to the intensity of erythema, which acts then as " no landmark " . On the other hand in the part UVA of the spectre, this link is not any more proved and in 380 nm, there is even a critical zone where the risk of cancer is distinctly superior to that of erythema where from the necessity to protect itself well in UVA.

The carcinogenic power of UV is apparently established for the cancers of the pidermique part of the skin: these are carcinomas pidermo des and spinocellulaires. As for the cancers which attain the dermis, he is shown that some clever m lanomes happen ten-twenty years after a solar burn happened during childhood.

The statement of these attacks is therefore often the result of overexposures in the first years of life. It is for it that a photo protection adapted, instituted from l childhood, limits considerably the likelihood of cancerization of the skin.

What are incurred risks when beauty spots are insolated?

The beauty spot (or n vus pigmentary) is a m lanocytaire entity having suffered some benign disturbances of development. N vus is present to most individuals, particularly on the displayed zones.

For a type of skin give, they are numerous all the more as doses combined by solar exhibition were raised during childhood. In this title they are indicators of the individual risk of m lanomes.

N vus is zones with bigger likelihood of cancerization and those admitted to be atypical can be considered to be forerunners of m lanomes. Besides, family antecedents of m lanomes augment individual risk.

It is therefore essential to limit all types of attacks and particularly exhibitions in UV.

If for reasons of anatomic location, he proves to be difficult to avoid exhibition, a generous cover of N vus with a product having SPF (or FPS) extreme associate in a high protection UVA is a good compromise.

What the lucite? How is it possible to tell her?

Under the term of "Lucite" is implied the Lucite E.stivale B nigne (LEB). IL however needs to know that there are other forms of lacites morphologically close to the LEB but which are much rarer and that do not evolve in the same way; it is between others of the polymorphous lacites.

LEB, form of lucite the most spreading, is a photo dermatosis characterised by a reaction of photo-allergic type. Even if the triggering factor remains still unknown, UVA seems to contribute to the demonstrations of LEB.

This attack touches female subjects pr f rentiellement. Clinical signs happen from the first exhibitions in the sun and are characterised by raptions prurigineuses very often located on the neckline, the members but sparing the face.

To tell LEB, it is necessary to prepare the skin for a long time before solar exhibition. The absorption by oral way of certain molecule, two or three weeks before the beginning of exhibitions, contributes to minimise risks of cutaneous eruptions: carot no des has an effectiveness about 50 %, the anfi-paludal of 80 % synthesis about, PUVATH RAPIE of 90 %.

The external photoprotecfion, as a supplement to the named preventive measures, must be accomplished with SPF (or FPS) very high and with a spectre of photoprotecfion the broadest possible (UVB + UVA), because LEB can be launched in spite of very high IP UVB. If the applications of product (SPF> 75 and IP UVA> 10 or more so possible) are regularly performed, the increase of LEB is told in 60 - 80 % cases.

What is the effect of the sun on the acne?

The action of the sun on the polymorphous acne is in double sharp side. Indeed, during summer period the inflammatory element of the acne is very often improve and lesions regress. This aspect is erroneously encouraging because, from the end of exhibitions, an important recrudescence of the acne is noticed in most cases. This phenomenon, called hyper k ratose summer, is linked to a thickening of the horny layer led by UV: he procreates a blockage of the infandibulum (conduit of emergence of the pilo-sebaceous follicle). When the conduit is obstructed, the sebum cannot be any more eliminated by the follicular channel, there is s bacce retention and at the beginning of training of a comedo. On an acn ique skin, it is the detonator of a recrudescence of symptoms.

For acn iques skins, it is therefore important to limit exhibitions in the sun and to envisage a photo adapted protection, to tell side effects of UV of type hyper k ratose who are at the origin of the post summer increases of acne.

Herpes and the sun!

Herp is an illness of the skin and of mucous membranes due to a virus. It is the most frequent human viral illness. It is specific of the Man, it does not exist in animal kind.

The first contact with the virus of herpes is translated by a called infection  firstly - infection  , most often inapparente (90 % cases). The penetration of the virus in organism is made either by the skin, or at the level of mucous membranes (buccale, genital). Most often, I' origin of pollution is not found because she is made by persons having the virus in saliva or in genital secretions there 1 absence of any clinical symptom.

After its penetration in organism, the virus migrates in the nervous ganglions sensitive s which depend on the cutaneous or mucous territory where took place firstly - infection. The virus is going to persist in ganglions in the latent state (= in rest). It is the big biological feature of the virus of herpes. The virus in the latent state can be reactivated by various triggering factors: infection (bacteria, virus: influenza), the sun, stresses, rules, pregnancy. He manifests itself then by clinical symptoms at the level of the cutaneous or mucous territory where took place firstly - infection. It is what is called a herp tique (=r surgence) recurrence. The virus comes to re-colonize the initially attained cutaneous or mucous territory. C est ce qu on appelle une r currence herp tique (=r surgence). Le virus vient recoloniser le territoire cutan ou muqueux initialement atteint.

There are 2 big types of herpes:

• HSV 1, responsible of 1 herp s at the level of the mouth and of the upper part of the body,
• HSV 2, responsible of 1 herp s genital which is a sexually transmitted disease frequency of which is in regular increase.

The most common presentation of a herp tique recurrence is that of the "cold sore" at the level of lips. On lips or around lips appears a feeling of burn or of prickle followed by a small red plate of which come along on top small vesicles (= blisters) in clear contents put together in bunch. Vesicles break and lead to the training of cro telles. cro telles ends up falling and still leave during some days a red stain which fades progressively. The increase of herpes lasts 5 - 10 days.

The sun is a frequent triggering factor of l herpes of lips (25 % recurrences). It is often called  I' herpes of snows  because it appears more often to winter sports. It is principally UVB (290320 nm) that is responsible for it, probably by means of a reduction of immune system. Immunosuppression is spoken of photo.

An American study showed the effectiveness of the photo protection in the prevention of the herpes of lips: I' RADIATION UV does not launch herpes to the subject protog by the photoprotector [ultraviolet Prevention of - lightinduced herpes labialis by sunscrcen (Prevention of the labial herpes photo-led by a sunscreen).

What are the most proper hours to go out in the sun?

Photo biologists recommend to avoid the stages of exhibition where the radiance of the sun is the most intense. In summer, this stage is between 12 and 16 o'clock, the solar hour.

Indeed in Montpellier, from April 1st, an exhibition of one hour to the sun between 11 h and 12 h is enough so that a clear skin (phototype II) has the knack of the sun (that is 1 ryth male minimal dose or D.E.M.). At the beginning of July, half an hour about will be enough for having the knack even of the sun.

What are the most sensitive parts of the body in the sun?

The sensitivity in the sun for the same subject depends on different factors:

• The thickness of the horny layer
  The horny layer, constituted by structures pseudo crystalline formed by the keratin, represents a system of efficient broadcasting which limits the penetration of radiance in the skin. The more the horny layer is thick, the more this broadcasting is important. Conversely, if the horny layer is fine, UV can cross it and attain easily the deep parts of the epidermis.
• The degree of pigmentation during exhibition
  Pigmentation uvaux exhibition allows a first protection and limits therefore the effect of UV in comparison with the not pigmented zones. The part of the top of the foot, for example, is seldom displayed throughout the year and one not much alters the pigmentation therefore of it. So, it is not rare to contract a sunstroke on this zone if it was not protected well.
• The anatomic site
  Some anatomic sites are practically displayed always in summer whatever is the position of subject in comparison with the sun. It is the case of the top of shoulders and of feet or of the nose that, even if they are not particularly fragile, suffer exhibition permanently and accept such therefore from doses as if protection is not particularly watched, it is assured sunstroke.

So, the zones of the body which correspond to one of the criteria described above are to protect by higher indications than on other parts of the body by renewing regularly the applications of products.

How much times during the day, when they go out in the sun, it is necessary to delay some cream?

In a general way, the substantivit of an anti solar product (capacity of the product to stay on the skin) is function of its gal nique form who will make it more or less r manent on the skin. Besides, filters contained in I product and which absorb the energy of UV end up being corrupted and losing partly their initial power of absorption. It is for it that a product will not give the same photo protection at the time of its application on the skin and soon after.

This especially since there will be a bathing or perspiration. A study on children shown that the effectiveness of a product is optimum if the application of this one is renewed every 2 hours.