Transverse sections for diagnosis of alopecia?

Several authors have claimed usage of sections cut horizontally as being preferable to conventional cuts in vertical direction in the diagnosis of alopecias. In this article, we address in critical fashion, all statements that have been made in the literature that seem to favor sections cut horizontally in contrast to sections cut conventionally (ie, vertically) in coming to a diagnosis of diseases of the scalp. Our assessment reveals that the idea of horizontal sections being advantageous compared with sections cut vertically is based largely on the assumption that counting of follicles is the key to a diagnosis with specificity of diseases of the scalp. But a quantitative approach to diagnosis of alopecias is flawed; it does not allow differential diagnosis of common alopecias to be made with certainty. A qualitative approach, however, based on reliable and repeatable criteria applied in sections cut vertically, allows in most instances a diagnosis to be rendered precisely.