Increased hair shedding may be associated with the presence of Pityrosporum ovale.
OBJECTIVE
Although the available data show that hair loss is an important cosmetic problem worldwide, the pathogenesis of common hair shedding is not fully understood. The aim of this study was to evaluate the association between hair shedding and cutaneous Malassezia infection. Malassezia fungi have been the suspected cause of dandruff for more than a century. Previously referred to as Pityrosporum ovale or P. orbiculare, these fungi are now known to consist of at least seven species.


METHODS
Over a 4-year period, we obtained 300 hair samples from medical students. Based on the clinical history and a hair-pull test, the participants were divided into two groups: normal subjects and subjects with hair shedding. The students' scalp skin was gently scraped, smeared on a slide, colored by methylene blue, and observed under 10x magnification.


RESULTS
All participants who had positive smears with >or=3 P. ovale organisms per low-power microscopic field (10x) were defined as 'carriers.' Seventy-six percent of students were Malassezia carriers. The prevalence of positive smears was significantly higher among subjects with hair shedding than among normal subjects (89.92% vs 9.52%, p<0.001). Furthermore, participants with positive smears had a significantly higher frequency of hair loss complaints and positive hair-pull tests.


CONCLUSIONS
The proportion of subjects who were carriers of Malassezia yeasts was significantly higher in the group with hair shedding, and our results therefore raise the possibility of a relationship between this unicellular organism and hair loss. Our study findings should be explored in a larger series of patients.
Nematian
Javad
J
Department of Mycology, Faculty of Medicine, Azad University of Medical Sciences, Tehran, Iran.
Ravaghi
Mehrdad
M
Gholamrezanezhad
Ali
A
Nematian
Edwin
E
D000328:Adult; D016022:Case-Control Studies; D003881:Dermatomycoses / Q000382:microbiology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007039:Hypotrichosis / Q000382:microbiology* / Q000503:physiopathology*; D008290:Malassezia; D008297:Male