Cicatricial alopecia.

Cicatricial alopecias (CAs) are clinical pathological conditions that result in the complete destruction of hair follicles, which are replaced by fibrotic structures. Clinically they are characterized by different inflammatory conditions resulting in the end stage in the complete disappearance of hair follicle and follicular ostia. CAs are classified in primary cicatricial alopecia (PCA) and secondary cicatricial alopecia (SCA). PCA include multiple inflammatory diseases with distinctive clinical and histopathologic features that primarily affect and destroy the hair follicle. On the other way, diseases classified as SCA include inflammatory and neoplastic conditions and physical traumas usually primarily affecting the dermis and causing secondary follicular destruction.