[Psoriasis and infestation with Malassezia]

ABSTRACT

Psoriasis is a chronic proliferative condition of the skin. Its accurate pathogenesis has not been known yet but interactions between genes and environmental factors have been implicated in its initiation. Although several reports have associated this lipophilic yeast with development of skin lesions in Psoriasis, the definite role of this lipophilic yeast in psoriasis is still undetermined. Our aim was to investigate the correlation between Malassezia and psoriasis. In this six-month's case-control study, a sample was obtained from cutaneous lesions of 50 psoriatic patients and 50 healthy volunteers as control group for evaluation of Malassezia infestation. Data were collected by use of questionnaires and analysed by SPSS software and using statistical tests of X[2] and Mann-whitney. There is no difference between Malassezia infestation in scalp lesions of psoriatic and healthy persons [P=0.86]. Malassezia infestation in psoriatic patients with scalp involvement was more than those without scalp involvement, but this relationship was not statistically significiant [P=0.069]. There is an inverse significant relationship between scalp infestation with Malassezia and chronicity of psoriasis [P=0.04]. Infestation with Malassezia in body skin of psoriatic patients was less than normal persons [P< 0.000]. It seems that Malassezia has an initiating role in inducing immune mechanism involved in pathogenesis of scalp psoriasis by Malassezia, but with chronicity and formation of dry and hyperkeratotic plaques, the environment will be inappropriate for Malassezia, so Malassezia infestation decreases with chronicity of disease