A Study of Various Histopathological Features and their Relevance in Pathogenesis of Psoriasis.

Background: The pathogenesis of psoriasis is still to be fully unraveled. The immunological theory with T cells at the centre of attraction and peripherally acting cytokines are the present favourites among aetiopathological factors. Histopathology of the skin lesions offers a good study model to understand the pathogenesis of this complex disease. Aims: To study the various histopathological parameters of psoriatic lesions, and to establish their correlation with the pathogenesis of the disorder. Materials and Methods: Eighty eight consecutive histopathologically proven cases of psoriasis were included in the study. Eight common histopathological parameters of psoriasis present in these biopsies were assessed and graded. We then statistically analyzed the relationship of the factors with one another and attempted to establish a better understanding of the pathogenesis of disease. Results: Significant correlations were found between degree of epidermal hyperplasia and inflammatory infiltrate, grade of inflammation and pustules of Kogoj, inflammatory infiltrate and grade of capillary proliferation as also between epidermal hyperplasia and the presence of parakeratosis. Conclusion: The study suggests that the immunopathogenesis of psoriasis is predominantly based on the inflammatory response. This is in consonance with other studies which have suggested that psoriasis is primarily a T lymphocyte based disease. Several treatment modalities are now based on this concept and it is hoped that the future treatment modalities will focus on the central role of inflammatory cells in the pathogenesis of this enigmatic disease.