Assessment of Hair Loss: Clinical Relevance of Hair Growth Evaluation Methods

In 2002, M. D. Van Neste reviewed methods for assessing hair loss, emphasizing the need for a combination of analytical and global calibrated methods for effective monitoring in a clinical setting. The review discussed the strengths and weaknesses of invasive, semi-invasive, and noninvasive techniques, including scalp biopsies, trichograms, and phototrichograms. It highlighted the importance of understanding hair cycling and its impact on hair loss patterns. The review introduced a scalp coverage scoring method with high reproducibility (correlation coefficients >0.9) and discussed global photography, daily hair collection with findings challenging the 100 hairs per day norm, and hair weight and count methods. A study of 404 females showed a mean hair loss rate of 28 to 35 hairs per day, and another of 234 women indicated those with normal hair density shed fewer than 50 hairs a day. The document concluded that objective measurements are crucial due to the placebo effect and the complexity of hair growth, which varies across different scalp areas and is influenced by various factors.