Revisiting Diffuse Unpatterned Alopecia: Reappraisal of a Controversial Diagnosis

Diffuse unpatterned alopecia (DUPA) is thought to represent an uncommon and incompletely characterized variant of androgenetic alopecia (AGA) marked by diffuse follicular miniaturization across the entire scalp, including the occipital region, which distinguishes it from classic patterned AGA and often precludes hair transplantation. In this review of the available literature on DUPA, we discuss its clinical presentation, diagnostic features, competing pathophysiologic hypotheses, and management considerations. Current evidence suggests DUPA typically presents with diffuse scalp thinning involving the frontal, vertex, temporal, parietal, and occipital regions, with trichoscopy demonstrating widespread follicular miniaturization without features of scarring alopecia. Diagnosis remains clinical because histopathologic criteria and standardized trichometric thresholds have not been established. Important mimickers include telogen effluvium and diffuse alopecia areata, making careful history, examination, trichoscopy, and occasional scalp biopsy essential. Management is primarily medical, emphasizing stabilization rather than regrowth, and includes topical or oral minoxidil with consideration of adjunctive therapies such as platelet-rich plasma, low-level light therapy, and possibly antiandrogen therapies in selected patients. Major knowledge gaps remain regarding epidemiology, pathology, diagnostic criteria, and treatment-specific outcomes. Further clinicopathologic, trichometric, and longitudinal studies are needed to clarify whether DUPA represents a distinct entity or a severe diffuse phenotype within the AGA spectrum.