Case Report: Paired vertex-occipital assessment reveals donor-area involvement in diffuse unpatterned alopecia.

Diffuse unpatterned alopecia (DUPA) is an uncommon subtype within the androgenetic alopecia spectrum and is characterized by progressive diffuse thinning that may involve the entire scalp, including the occipital region, which is often presumed to represent a stable donor area for hair transplantation. We report two male patients with long-standing, progressive diffuse scalp thinning in whom paired vertex-occipital assessment demonstrated donor-area involvement. Quantitative trichoscopy showed increased hair-shaft diameter variability and elevated miniaturization in both the vertex and occiput, with consistently greater involvement in the vertex. Synchronous 4-mm punch biopsies from the vertex and occiput confirmed follicular miniaturization at both sites, with reduced terminal-to-vellus hair ratios and increased proportions of miniaturized follicles, supporting a diagnosis of DUPA and indicating the absence of a reliably stable donor zone. Both patients received medical therapy with oral finasteride and topical minoxidil. At 6 months, objective follow-up showed increased non-vellus hair density and reduced trichoscopic miniaturization in both scalp regions, consistent with short-term stabilization and partial improvement. This case series highlights an important diagnostic and management pitfall: if occipital sparing is assumed rather than verified, donor-area involvement may be overlooked and procedural counseling may be inappropriate. Paired vertex-occipital trichoscopy, with confirmatory biopsies when management decisions depend on donor stability, can improve diagnostic confidence, guide longitudinal monitoring, and inform medical and surgical counseling.