[Cicatricial alopecias: diagnosis and therapy]

The cicatricial alopecias often are both a diagnostic and therapeutic challenge to the practitioner. Where there is no obvious physical/chemical injury or acute infectious etiology, clinical differential diagnosis of scarring alopecia is often difficult. The loss of follicular orifices in an area of alopecia points to a permanent loss of hair. In all of these cases a scalp biopsy is indicated. Primary and secondary scarring alopecia are differentiated: While the former is due to preferential destruction of the follicle, the latter results from events outside the follicle, which eventually impinge upon and eradicate the follicle. These include infiltrative processes such as granulomatous inflammation or neoplastic disease. In the group of primary scarring alopecia, well-defined chronic-inflammatory diseases of the scalp amenable to specific therapies are differentiated microscopically on the basis of the pattern of inflammation and the type of inflammatory cell that predominates. Thus, accurate diagnosis based on histopathology is a prerequisite to any rational therapy. Management of the less well classified diseases is much more problematic. Where end-stage fibrosis is established, surgical treatment and/or prosthetic help are taken into consideration. With the expanding knowledge of the immunology and molecular biology of the hair follicle, there is hope for the feasibility of therapeutic interventions that interfere early in the course of the pathogenetic processes ultimately leading to the permanent loss of hair.