Résumés
Résumé
Conséquence d’un renouvellement accéléré de l’épiderme entretenu par une inflammation chronique, le psoriasis associe, sur un terrain génétique particulier, une hyperréactivité variable de plusieurs gènes. La maladie se présente comme une réaction exagérée de la peau aux agressions de la vie quotidienne, qu’elles soient exogènes ou endogènes, ces agressions entraînant une libération excessive de cytokines pro-inflammatoires aboutissant au déclenchement d’un processus inflammatoire qui rend la maladie chronique. En fonction des modes successives, l’attention des chercheurs s’est portée sur les anomalies de la peau ou sur les anomalies des cellules inflammatoires caractéristiques de l’inflammation psoriasique. En fait, il semble maintenant nécessaire d’étudier les anomalies génétiques et les anomalies des voies de signalisation qui aboutissent à une sécrétion excessive de cytokines pro-inflammatoires, mais aussi de mieux comprendre les interactions entre cellules cutanées et cellules inflammatoires. Les progrès thérapeutiques récents, dans le traitement du psoriasis, reposent avant tout sur la mise en place de techniques permettant un meilleur ajustement des outils thérapeutiques aux besoins des patients. De fait, si le psoriasis met rarement la vie en danger, il atteint souvent gravement la qualité de la vie : l’objectif est donc d’élaborer une stratégie thérapeutique qui améliore cette qualité de vie, que seul le patient peut évaluer. Cette stratégie, permettant d’ajuster les possibilités thérapeutiques à chaque patient, repose sur quatre phases successives : le questionnement, qui permet d’évaluer la gravité de la maladie, les explications, qui permettent au malade de comprendre comment il peut agir sur sa maladie, la négociation, qui devient l’acte médical principal, et doit aboutir à une décision thérapeutique partagée. Il s’agit là d’une révolution, au sens propre, dans la relation entre le médecin et le malade : l’éducation du patient se situe au coeur de la démarche thérapeutique. C’est dans ce contexte que sont apparus de nouveaux médicaments, très intéressants sur le plan scientifique et apportant l’espoir d’une efficacité raisonnable, associée à une bonne tolérance. Ces médicaments sont toutefois très coûteux, ouvrant en cela le débat des possibilités et des limites de la solidarité.
Summary
Psoriasis is a model disease in dermatology. It is a common disease that affects at least 2 to 3 % of the population. It is an illness characterized by an excessive reaction of the skin, in term of proinflammatory cytokines release, to no specific attacks: these attacks can be immunological, mechanical, metabolic, drug-induced or psychological. This excessive reaction is characterized by epidermal proliferation combined with incomplete terminal differentiation, as well as an inflammatory response responsible for the chronic nature of the lesions. The way to understand psoriasis is therefore to reach a better appreciation of the messages that enable the skin cells to initiate an inflammatory response, and by better understanding the way in which the inflammatory cells responsible for innate and acquired immune responses are capable of bringing about proliferation and abnormal epidermal differentiation. Taking an interest in psoriasis is therefore taking an interest in all facets of skin physiology and in all the ways the skin reacts to attacks from the environment. Every year for more than thirty years, more than 300 publications have endeavoured to explore one aspect or another of psoriasis from a clinical, epidemiological, physiopathological or therapeutic point of view. There is no new technique for observing the skin that has not been immediately applied to the study of psoriasis - which is privileged to enjoy the reflected progress made in dermatology. Nor has psoriasis remained untouched by whims of fashion, all manner of scenarios having been suggested to explain it, right from a scarring disease to an autoimmune illness through a genetic or psychosomatic disorder. Psoriasis is at the origin of a medical revolution mounted to supplement and enhance the effectiveness of evidence-based medicine ; it is the “patient-centred medicine”. Psoriasis only exceptionally jeopardizes life. Conversely, it is a disease that does affect quality of life. The patient alone must be the judge of his or her quality of life, and it is therefore up to the patient, not the doctor, to gauge the severity of psoriasis and hence decide on reasonable therapeutic indications. Psoriasis, then, cannot be treated without placing the patient, not the illness, at the centre of therapeutic negotiations. The 20th century has seen the disease targeted by boundless efforts ; the 21st century will see the development of medical techniques that allow the patient, in all its complexity, to be positioned at the centre of therapeutic efforts. This revolution began in dermatology, centring around psoriasis, and is spreading progressively to all chronic disorders and all disciplines. New quite interesting therapeutic weapons are available from a few months making possible to better adjust the therapeutic strategies of psoriasis to the patients needs but they are expensive opening again the debates on the limit of the social solidarity.
Parties annexes
Références
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