[Cicatricial alopecias].

Cicatricial alopecias are a diagnostic and therapeutic challenge. The irreversibility and cosmetic sequelae of cicatricial alopecia demand special diagnostic attention. Loss of follicular orifices points to permanent hair loss, due to irreversible damage to essential parts of the follicle or destruction of the entire follicle. Where there is no obvious physical/chemical injury or acute infectious etiology, clinical differential diagnosis may be difficult. Clinical inspection is of limited usefulness. Accurate diagnosis based on a careful patient history, examination, microbiological studies, and scalp biopsy are prerequisite to therapy. On the basis of histology, a differentiation is made between primary cicatricial alopecias due to preferential destruction of the follicle, and secondary cicatricial alopecias resulting from events outside impinging upon and eradicating the follicle. The primary cicatricial alopecias include well-defined chronic inflammatory diseases differentiated depending on the type and pattern of inflammation. Although clinicopathologic features allow for diagnosis in most cases, therapeutic limits reflect the boundaries of our present understanding. With expanding technologies for dissecting the immunologic and molecular basis, there is hope for a deeper understanding of the underlying pathogenesis and novel therapeutic interventions.