Frequency of the Types of Alopecia at Twenty-Two Specialist Hair Clinics: A Multicenter Study

The frequency of different types of alopecia is not clearly reported in recent studies.

To analyze the frequency of the types of alopecia in patients consulting at specialist hair clinics (SHC) and to assess for global variations.

Multicenter retrospective study including data from patients evaluated at referral SHC in Europe, America, Africa and Australia.

A total of 2,835 patients (72.7% females and 27.3% males) with 3,133 diagnoses of alopecia were included (73% were non-cicatricial and 27% were cicatricial alopecias). In all, 57 different types of alopecia were characterized. The most frequent type was androgenetic alopecia (AGA) (37.7%), followed by alopecia areata (AA) (18.2%), telogen effluvium (TE) (11.3%), frontal fibrosing alopecia (FFA) (10.8%), lichen planopilaris (LPP) (7.6%), folliculitis decalvans (FD) (2.8%), discoid lupus (1.9%) and fibrosing alopecia in a pattern distribution (FAPD) (1.8%). There was a male predominance in patients with acne keloidalis nuchae, dissecting cellulitis and FD, and female predominance in traction alopecia, central centrifugal cicatricial alopecia, FFA, TE, FAPD and LPP.

AGA followed by AA and TE were the most frequent cause of non-cicatricial alopecia, while FFA was the most frequent cause of cicatricial alopecia in all studied geographical areas.