**1. Introduction**

Hair loss is the most common hair disease and diagnosis of the type of alopecia may sometimes be challenging. Methods commonly used to investigate can be classified as either invasive (e.g., biopsies in scarring alopecia), semi‐invasive (trichogram, unit areatrichogram), or noninvasive (e.g., hair count, weighing shed hair, pull test, global hair counts, dermoscopy,

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

phototrichogram, electron microscopy, laser scanning microscopy) methods. In this chapter, I will try to explain the basics of trichoscopy and trichogram.
