The study of incidence and distribution of pityrospoum on clinically normal skin

Cha, Hyoung Gi; Moon, Doo Chan; Kwon, Kyoung Sool; Chung, Tae Ahn

Abstract

BACKGROUND: Previous studies have suggested that pityrosporurr yeasts, normal resident flora of skin, may be important in the pathogenesis of dandruff seborrheic dermatitis and confluent and reticulated papillomatosis.
OBJECTIVE
We investigated the incidence and distribution of pityiosorum yeasts on clinically normal skin as a more reasonable method for providing the basic data or proving the relationship of pityrosporum and pathogenesi, of the diseases. MEHTODS: A total of 350 subjects were studied. Skin scrapings were stained with 20% Parker ink-KOH(P-KOH) solution. The numbers of pityrosporum spores and hyphe per high power field( x 400) were counted and designated according to a new grading method using bacterial index(BI) of lepra bacilli.
RESULTS
The incidence rates of pityrosporum orbiculare(p. orbiculare) and pityrosporum ovale(p. ovale) were 60-70% and 20-50% of subjects respectively on seborrheic area., The incidence of p. orbicilare was highter than that of p. ovale on all examined sites except for the iterior scalp. And pityrosporal hyphae was present on anteriand posterior scalp and earwax in 24-25% of subjects respectively. The incidence of pityrosporum was higher in summer than other seasons The incidence rate of p. orbiculare and hyphae in the group aged below 9 (except neonates) and above 60, were lower than that of other age groups. The inciderice rates and distribution of grades of pityrosporum of neonates were lower than those of older subjects.
CONCLUSION
The results of this study showed that the incidence and distribution of pityrosporum spores were similar to previoureports and hyphal forms were found 25% approximately on clinically normal skin of the scalp and carwax. The significance of the presenet of pityosporal hyphae and the relationship between normal skin and pityrosporal hyphae are to be firther elucidated.