The psoriasis is a disease of the Peau of badly known origin, partly genetic. This dermatological affection touches 1 to 3% of the population, as well at the women as at the men.

In its benign form, the psoriasis is limited to the scalp, the nails, the knees, the elbows, the feet, the hands and, sometimes, the genitals. In the serious cases, it extends and can gain the totality of the body.

This chronic dermatosis evolves/moves in a very individual way, with pushes, but also of the remissions during which the lesions disappear. It is said whereas the psoriasis “is bleached”. The respite is of duration very variable and the often incomplete remission.

To date, no curative treatment making it possible to cure psoriasis completely is known; it is however possible to control the psoriasis, to decrease the extent of the lesions and to improve the life of the patients. .

History

One of the first precise descriptions was done by it by the British Robert Willan in his treated skin diseases going back to 1808.

Causes

The precise causes are unknown although, in a certain number of cases, one can find a family origin. The disease would have components genetics, auto-immune, microbiological and environmental.

The skin is renewed too quickly, in only four to six days, instead of the three weeks usual what generates localized ignitions. The épidermiques cells accumulate on the surface of the skin and form a layer of white films called squames. Perfectly inoffensive, those have the disadvantage to however be unaesthetic. The presence of many Leucocyte S in the Derme suggested the role of the Immune system.

There exists a family component with the psoriasis: nearly 30% of the patients reached have a member of their family having also the same disease. A certain number of genes were identified as potential markers of risk, of which PSORS . Most important seems to be PSORS1 located on the chromosome 6 and which would be responsible of almost the third to the family psoriases.

The pushes of psoriasis are sometimes related to stresses. They can also have for origin an infectious factor (streptococcic infection, for example). Their frequency is very variable and, generally, the factor starting of thorough is not identifiable. The alcohol excessive consumption is a factor of aggravation of the psoriasis.

Certain drugs exacerbate sometimes the psoriasis but their stop must be discussed on a case-by-case basis, that Ci being able to involve other risks, cardiovascular in particular. They are primarily those of the class of the Bêta-bloquant S. Of other molecules were brought back like potentially worsening, with a however less risk. They are the Sartan S and the énalapril.

On the contrary, the solar exposure has a protective role Net.

Epidemiology

Its prevalence is variable according to the ethnos group: it is more frequent at the person of white race, concerning between 1 and 3% of the population. To appear, this inflammatory affection needs a hereditary ground and a starting factor. If one of the two parents is reached, the risk for the child to develop it is from 5 to 10%.

Types of psoriasis

Psoriasis in plates

Also called psoriasis vulgaris , it is about the most current form of the psoriasis (more than 90% of the cases) which gave its name to the disease: " large squames". The cutaneous lesions red, are irritated, squameuses and are infiltrated. The central area is normal. When the squames are detached, they leave the skin to sharp, sometimes bleeding.

The localization of the plates is about symmetrical, relating to the area of the elbows primarily, of the knees, the scalp, the bottom of the back or the perish-umbilical area. It can reach also zones previously cicatricial or on which traumatisms ( Phénomène of Koebner ) are exerted.

Psoriasis in drops

The psoriasis drips about it (or psoriasis guttata ), as its name indicates it, is characterized by a scattering of small drops of psoriasis on all the body. One does not observe plates but drops, which have the advantage, from their reduced size, of " blanchir" more quickly and thus to remain " irritantes" with sharp less longer. One finds them on all the zones of friction: low belly, low of the back (size of the pants) front armlever, turn of chest (bras) but also hair and external house of the ear.

Pustuleux psoriasis

It results from the exaggeration of the phenomenon of exocytose the polynuclear ones which characterizes the psoriasis; clinically: pustules punts white-yellowish (amicrobiennes) with a tendency to coalescence. Histologically: spongiform pustule of Kogoj. This type of psoriasis is in general palmo-plantar. One as speaks about acropustulose to mean as it relates to the ends.

Psoriasis reversed

When the psoriasis reaches the folds of the inflections, the lesions different, squameuses, are irritated, sometimes oozing.

Psoriasis erythrodermic

It is a érythémato-squameuse attack of the totality of the tegument, which is red, œdémateux, cover of squames fine which is eliminated in large scraps. There exist general signs (fever, anorexia) and adenopathies. The risks are: superinfections, metabolic consequences of the 3rd cutaneous sector (hypovolemy), hoop nets hydroelectrolytic, the decompensation of a tare. The hair and the nails can secondarily fall.

Attack unguéale

The attack of the Ongle is present in half of the cases of psoriasis) of psoriasic, and joins in general cutaneous lesions (which, seldom, can begin after rheumatism). It is a chronic inflammatory rheumatism, deforming, which can be very invalidating, which one describes two great forms, which can be associated:

• axial Rheumatism: aspect very close to the rheumatic Pelvispondylite: SPA (neck, back, Sacro-iliaque S) and generally occurs at men carrying the HLA-B27.

• peripheral Rheumatism: aspect close to the polyarthritis rhumatoïde, with however a predilection for inter phalangeal distal (the skin of the fingers, the nails, are generally reached psoriasis).

No association with the HLA-B27.

Certain forms can develop following an articular traumatism.

Other effects

Effect on the quality of the life

Unaesthetic effect handicapping the subject in its daily life

Cardiovascular effects

The carriers of psoriasis would have a greater risk to make a Myocardial infarction, more especially as the attack is wide.

Evolution

It is done by thorough with remissions (cure connects) more or less complete reaching a few tens of years sometimes.

Histology

The examination under the microscope of a sample of skin reached is hardly useful in practice current, the diagnosis being generally obvious.

This examination shows an increase thickness of the skin, the presence of many particularly tortuous blood-vessels in the Derme with infiltration in this last by Leucocyte S.

In skin unfulfilled, the examination under the microscope is strictly normal.

Treatment

Local treatment

The local treatment consists in applying a cream to the zone of the psoriasis.

• Corticosteroids: the latter have a favorable effect on the psoriasis, unfortunately the plates often return as of the stop of the treatment. This last also generates a form of insensibilization, which obliges to increase the amounts in time. Moreover, the effect is not only any more local if one applies these pomades to vast zones. This form of treatment should thus be limited to acute or strongly unaesthetic forms, for one short period and on a limited surface.
• Calcipotriène : the calcipotriol is a derivative of the Vitamine D. Normally, the latter is synthesized during the exposure of the skin to the solar ultraviolet light. It is thus here about a substitute to this exposure (or with the puvathérapie). The applicable maximum quantity is however limited, because, with strong amounts, the calcipotriol becomes toxic.
• Rétinoïdes: the Tazarotène is a derivative of the Vitamine has available in pomade. Its tolerance would be however less than the calcipotriol.
• tar: they before were frequently used in application on the psoriasis but were malcommodes because particularly dirtying.
• Anthralène : the dithranol is a derivative of the tar. The dithranol has a certain effectiveness, especially in partnership with other treatments but it is sometimes irritating and especially inconvenient (very " tachant"), which in limit its use.
• Salicylic acid;
• propionate of clobétasol;
• Baths;
• Hydrating skin.

These local treatments can be possibly associated.

Phototherapy

• the solar exposure generally has a favorable influence on the psoriasis. However, in 10% of the cases, this exposure will be in fact harmful. The subject will have to then avoid the sun, or at least to avoid being directly exposed with its rays;
• Phototherapy with the Ultraviolet B (UVB): In all the cases, the ultra-violet therapy (has or B) must be realized under medical control. It leads to a variable tolerance level from one individual to another which it is necessary not to exceed: oxydative capital. Without that the patient exposes himself to the heliodermy and the risks - weak of cutaneous cancers (épithélioma, melanomists). All the more weak risks as a suffering patient of psoriasis has much more dermatological controls than the " commun run of the mortels". what makes it possible to detect very possible neoplasy beginner as soon as possible.

• Puvathérapie or PUVA Psoralène and phototherapy with the ultra-violets A). The exposure to the only ultra-violets has (such as they are produced in the cabins of bronzing) has little effectiveness. The administration of psoralene in tablets, little before the exposure, the UVA, allows a sensitizing of the skin the latter. It exposes however to the risk of photosensitization ( sunstroke ) with burns. The puvathérapie is used since the use growing of the UVB, more handy.

• Phototherapy combined with other therapies

Systemic treatment

For the most severe forms of psoriasis, the doctors can prescribe treatments by oral way (pill) or injection. These treatments are called systemic because the drugs are judicious to be disseminated in all the organization. They often have side effects, sometimes serious.

• the Méthotrexate is an antagonist of a vitamin, the Folic acid
• Rétinoïdes: a Rétinoïde, the such Acitrétine, is a compound which has properties close to the vitamin has being able to be prescribed for the serious forms of psoriases which do not answer the other therapies. However, these treatments can cause malformations with the birth in the event of pregnancies of the patient. The majority of the patients present a resurgence of the psoriasis after the stop of the product.
• Cyclosporine : the psoriasis being considered near to the autoimmune diseases, a immunodepressor as the ciclosporine can sometimes produce positive effects, but its side effects are important (mainly because of the weakening of the immunizing defense system).
• 6-Thioguanine
• Hydroxyurée
• the Alefacept is an antibody directed against of the receivers of some lymphocytes T. It allows a substantial reduction of the severity of pushed with a preserved effectiveness at least in the medium term.
• the Efalizumab is also a monoclonal antibody directed against a certain type of leucocytic receivers with an effectiveness in the short and medium term for the light psoriasis with moderate. The Phytotherapy ( wild Burdock, Thought and Salsepareille is sometimes used|July 3rd, 2007 with 21:19 (CEST) ). Some Nutritrithérapie ( The Nutrition Seignalet |July 3rd, 2007 with 21:19 (CEST) , are also sometimes used in the psoriasis and the rheumatism psoriasic, treatment whose effectiveness is very disputed by the medical community).

Inter alia new treatments, marine lecithin is in the course of evaluation and of the positive tests were already published.

External bonds

• Association For the Fight Against the Psoriasis

References

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