Introduction: The diseases causing chronic diffuse alopecia and having similar clinical findings, namely chronic telogen effluvium, androgenetic alopecia, and the alopecia with overlapping features, should be differentiated. Recently, diffuse variants of lichen planopilaris have been described with histopathologic features of lichen planopilaris but clinically presenting with diffuse hair loss mostly in an androgenetic pattern. Objectives: To determine the accurate diagnosis underlying chronic diffuse alopecia in women by evaluating histopathologic findings. Patients and methods: The study included 32 patients with diffuse and clinically noncicatricial alopecia for at least 6 months with no identifiable etiologic factor after general medical history, review of organ systems, and appropriate laboratory tests. Two 4 mm punch biopsies, one from vertex and the other from mid‐occiput, were obtained and sectioned transversely. Results: The median age was 30.5 years (range: 22–40 years), and the median duration of hair loss was 4 years (range: 1.5–10 years). The histopathologic diagnosis was androgenetic alopecia, chronic telogen effluvium, and overlapping alopecia in 13 (40.6%), three (9.4%), and four (12.5%) patients, respectively. In the remaining 12 (32.5%) patients, a lichenoid inflammatory reaction affecting the infundibulum and isthmus was noted, and the probable diagnosis of diffuse variant of lichen planopilaris was made. Limitations: The retrospective nature and the small sample size. Conclusion: When the clinical diagnosis is not straightforward and no etiologic factor is found, histopathologic examination is mandatory for the accurate diagnosis of the disorder leading to chronic diffuse alopecia in women. [ABSTRACT FROM AUTHOR]