Background: We reviewed the literatures focusing on trichogram and comparing it with other newly introduced trichologic diagnostic methods (to be specific trichoscopy).

Methods: This is a narrative review. We searched PubMed, Scopus, EMBASE and the Web of Science for most relevant and English publications using the terms ‘trichogram’ or ‘phototrichogram’ or ‘trichoscan’ or ‘unit area trichogram’ or ‘trichoscopy’.The results were then screened by two independent reviewers and discrepancies was reviewed by another author. The text and data related to these terms were then selected out of each included study and discussed with all authors for inclusion in this study.

Results: There are many hair disorders with diagnostic clues of trichogram such as Alopecia areata, Androgenic alopecia, Anagen effluvium, Telogen effluvium, Trichotillomania, Pemghigus, Psoriasis, and Loose anagen syndrome. Trichoscopy have become a widely used non-invasive practical diagnostic tool for evaluation of many immune-mediated or non-immune mediated dermatologic disorders with involvement of hair. Trichoscopy is also commonly used for following up and evaluating the therapeutic responses in affected hair-bearing area.

Conclusion: Trichogram is a valuable diagnostic method for complicated hair disorders butthe trend is toward less aggressive and more sensitive informative methods like trichoscopy and trichoscan.

Key words: Trichogram, Trichoscopy, Phototrichogram, Trichoscan, Unit Area Trichogram, Dermatoscopy, Dermoscopy, Hair, Alopecia, Scalp, Diagnoses