الفهرس 
Introduction & Aim of the StudyOnly 14 pages are availabe for public view
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Abstract
Psoriasis is a serious inflammatory skin disease affecting about 2.5% of general population; it has been considered to be a single disease entity, characterized by a spectrum of well-defined clinical symptoms. It is based on this assumption that the vast majority of genetic, pathophysiological and therapeutic research has been conducted in this disease.
An alternative hypothesis is that psoriasis represents a common clinical expression pattern of different inflammatory skin diseases, each resulting from different specific pathophysiological processes and responding better to different treatments, indeed several findings support this later hypothesis. In particular, patients with early and late onset psoriasis often show different clinical and evolutionary features, plaque thickness has been reported to be another interesting clinical feature which differentiates psoriasis subtypes, phenotypes of psoriasis has also been investigated by comparing patients with different expression of HLA markers, or with different clinical manifestations at the first episode of the disease and many more.
It was accepted that there is a distinct phenotypes of psoriasis and it is important to come to consensus on classification of phenotypes of psoriasis such consensus will simplify stratification of psoriasis phenotypes and facilitate their link to confirmed investigational data.
The objective of this study was to use statistical exploratory multivariate data analysis approach that does not rely on any previous deterministic hypotheses concerning the discremenating characteristics of phenotypes, to identify potential clinical psoriasis phenotypes without prior hypotheses. A prospective questionnaire-based survey collected comprehensive information`s on the main clinical characteristics of 1181 psoriatic patients.
Six statistically different clusters of clinical symptoms were observed in Egyptian patients, corresponding to at least six different psoriasis phenotypes which may have important implications for future research in the field of psoriasis.
The major differences in these identified subtypes are principally:
• Body sites affected by psoriasis during the most severe flare of the disease.
• Clinical aspect of the disease.
• Age of onset of psoriasis in addition to other differentiating clinical criteris including; clinical course, association with psoriatic arthritis, atopy, pruritus,triggering factors and wieght gain, effect of sun light and sea water on the lesions, presence of familial antecedents of psoriasis, psoriatic arthritis, atopy and finally co-morbidities.
The existence of these phenotypes does not necessarily imply that they represent different disease forms. Our findings indicate that the large palette of clinical manifestations and wide range of body areas involved during the most severe flare of the disease and not only the selection of the most severe cases are important critical keys in evaluation and categorization of psoriatic patients. Psoriatic phenotypes description provides useful tools to evaluate whether this is the case in future studies or perhaps suggesting a specific genetic component to these phenotypes.
In conclusion; this study has identified six distinct clinical phenotypes of psoriasis in Egyptian patients, suggesting the existence of different subtypes of psoriasis disease and not just an expression of clinical features, which may reflect different pathophysiological processes in the development of this disease.
The change of the perspective about psoriatic patients would help more in assigning better and suitable treatment strategies with avoiding some complications that could be expected. In addition to conducting genetic, pharmaco-genetic, patho-physiological and therapeutic studies typically tailored to suite specific patients’ phenotypes.
It is recommended; to carry out more universal evaluation and investigation of psoriasis phenotypes among different ethnic patient groups are of high importance and necessity as association of different clinical symptoms, biological and genetic markers should provide interesting new information and allow further refining of the proposed phenotypic classification.