ABSTRACT
The causative role of Pityrosporum ovalea(P. ovale) in the development of seborrheic dermatitis has been disputed for many decades. Using Giemsa stain, the number of P. ovale adherant to extrutidei from one keratinocyte of the scalp were counted in twenty patients with seborrheic dermatisis and twenty control persons. Ths result showed that the number of P. ovale in patient with seborrheic dermatitis were significantiy higher than in the normal control group. Furthermon not only were the number of P. ovale decreased, but the clinical lesions were also significantly improved after a 4 week trial of oral itraconazole in the seborrheic dermatitis group. From this points of view, P. ovale may be one of the important causative factor of seborrheic dermatit.is.