This single-center, retrospective case series was conducted at the Department of Dermatology, Nizip State Hospital, Gaziantep, Türkiye, including consecutive patients with alopecia who underwent trichoscopic evaluation: LPP (n=7), DLE (n=7), and AA (n=14). The diagnosis of AA was made based on clinical and trichoscopic criteria, whereas all LPP and DLE cases were histopathologically confirmed. Age and sex were retrieved from medical records.

Routine polarized dermoscopy images were reviewed using a prespecified 16-item checklist (present=1/absent=0), including perifollicular scale, erythema, and casts; blue-gray target dots; follicular ostia loss or plugs; yellow and black dots; white scar or atrophy; background erythema; arborizing vessels; interfollicular scales; exclamation-mark, broken, and lonely hairs; and tufting.

Arborizing vessels were graded by caliber (0=absent, 1=thin <50% of adjacent hair-shaft caliber, 2=thick ≥50% of adjacent hair-shaft caliber).

Categorical variables were summarized as n (%) and continuous variables as mean (SD). Prespecified contrasts used two-sided Fisher exact tests (α=.05): AA versus scarring alopecias (LPP+DLE) for exclamation-mark hairs, yellow dots, white scarring or atrophy, and follicular ostia loss (plus exploratory black or broken hairs), and DLE versus LPP for follicular plug, arborizing vessels (any/thick), interfollicular scale, and peripilar casts.

Odds ratios were estimated with a Haldane–Anscombe 0.5 correction when zero cells occurred. Analyses were performed using Python and SciPy.

The study was conducted in accordance with the Declaration of Helsinki. Ethical approval was granted by the Scientific Research Ethics Committee of Bezmialem Vakıf University, Istanbul, Türkiye (Approval No: E-54022451-050.04-122609; September 6, 2023). The protocol originally focused on AA; additional LPP and DLE cases collected under the same protocol were analyzed here as a secondary evaluation, with notification to the ethics committee. All participant data were anonymized and deidentified before analysis. Owing to the retrospective design and use of anonymized data, informed consent was not required. No compensation was offered to study participants.

This study identified key trichoscopic patterns that reliably distinguish nonscarring from scarring alopecias. In this cohort, white scarring or atrophy and follicular ostia loss occurred exclusively in LPP or DLE and were absent in AA, reinforcing that the loss of follicular openings is a practical hallmark of cicatricial disease [5]. Conversely, AA showed clusters of exclamation-mark hairs and, secondarily, yellow dots; these markers also track AA activity and severity in structured trichoscopic scoring systems such as STRIAA (Severity Trichoscopy Index Alopecia Areata) and support their use as practical rule-in signs [6].

Among scarring alopecias, the findings of this study were consistent with those in previous reports [3,7,8]: DLE showed more follicular plugs and occasional thick arborizing vessels, whereas LPP consistently demonstrated perifollicular scale, frequent erythema, and characteristic target-pattern blue-gray dots [3,7,8]. Notably, lonely hair is not disease-specific and should be interpreted in context, particularly when differentiating LPP from frontal fibrosing alopecia [7].

Clinically, a succinct rule emerges: AA is favored by one or more of exclamation-mark hairs or yellow dots, whereas the combination of ostia loss and white scarring favors LPP or DLE. This aligns with stepwise diagnostic algorithms that first classify distribution, then scarring status by the presence or absence of ostia, and finally apply a short list of trichoscopic clues [9]. Comparative clinicopathologic studies also demonstrate systematic differences between DLE and LPP at the population level, providing additional context for our observations [10].

Key limitations include the small, single-center sample and limited power for LPP–DLE contrasts. Nevertheless, the direction and magnitude of the observed effects and the identified high-yield markers are consistent with contemporary systematic reviews [3] and support the external validity of the findings of this study.

A minimalist trichoscopic rule effectively differentiates AA from scarring alopecias: exclamation-mark hairs or yellow dots favor AA, whereas the combination of follicular ostia loss and white scarring favors LPP or DLE. These easily recognizable cues can assist clinicians in biopsy site selection and treatment planning. Larger multicenter studies are warranted to validate these findings and refine diagnostic criteria for distinguishing LPP from DLE.