Primary cicatricial alopecia is a potentially irreversible process of hair loss, in which for proper diagnosis a skin biopsy is necessary. Searching for new, non-invasive diagnostic methods may shorten the time for final diagnosis, initiating appropriate treatment and reduce the need for biopsy. The aim of this study was to evaluate the usefulness of high-frequency ultrasonography (HF-USG) as a diagnostic method in patients with primary scarring alopecia and to compare it with trichoscopy.