Frequency of Types of Alopecia in a Single-centre Hair Referral Clinic Over a Ten Years Period.

Background: The frequencies of the different types of alopecia in hair referral centres have so far been reported in a single multicentre study at multiple specialist hair clinics over a time period of one month. Aim: Single center studies over a longer time-frame offer a more representative and homogeneous study population with regard to ethnic, demographic, and climatic factors, and seasonality of hair growth and shedding than multicenter studies over a short time frame. Materials and Methods: Retrospective study of patient data at a single centre over 10 years. Results: A total of 15'211 patients (73% female, 27% male) were included, and we found the following frequencies: pattern hair loss (67%), alopecia areata (11%), the cicatricial alopecias (11%), and telogen effluvium (7%). Among the cicatricial alopecias, the most frequent diagnosis was frontal fibrosing alopecia (33% of cicatricial alopecias), followed in order of frequency by lichen planopilaris (19%), fibrosing alopecia in a pattern distribution (18%), folliculitis decalvans (8%), discoid lupus (5.5%), and dissecting cellulitis (2%). Some specific types of alopecia were observed more frequently in women, others in men, with a predominance of central centrifugal cicatricial alopecia and traction alopecia in women of African origin, and dissecting cellulitis of the scalp and acne keloidalis in men of African origin. The proportion of patients under the age of 10 years was 2.4%. Among the pediatric hair conditions were in order of frequency: alopecia areata (39%), prepubertal pattern hair loss (24%), telogen effluvium (6%), hereditary hypotrichosis (6%), congenital triangular alopecia (4%), short anagen hair (4%), loose anagen hair (3%), trichotillomania (2%), and tinea capitis (1.4%). Conclusion: Knowledge of the main types of alopecia and of their epidemiological and clinical specifics are prerequisite for providing an understanding of the etiologies and appropriate patient care in a respective specialty clinic.