Psoriasis vulgaris is a common, chronic, recurrent, inflammatory disease of the skin characterized by round, erythematous, dry scaly plaques of various sizes. The lesions have predilection for he scalp, nails and extensor surfaces of limbs, elbows &knees. Psoriasis is characterized by three main pathogenic features: abnormal differentiation, keratinocyte hyperproliferation & inflammation .Accelerated epidermopoisis has been considered to the fundamental pathologic event in psoriasis (1). The cause for that is still unknown, however, psoriasis is thought be to an auto-immune disorder influenced by some inheritance interplaying with acquired environmental factors (i.e. stress, hypocalcaemia, hormonal disturbances, infections).Due to the strong association between microbial skin flora &infections influencing psoriasis, we should focus on this flora & its change.
