Early Inflammatory Signals May Precede Alopecia Areata Diagnosis

Data from a new systematic review presented at the 2026 American Academy of Dermatology Annual Meeting indicated a consistently elevated neutrophil-to-lymphocyte ratio (NLR) in alopecia areata (AA).

Investigators used data from PubMed, Embase, and Cochrane databases following PRISMA guidelines, focusing on commonly studied hematologic ratios [neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII)]. Five studies met inclusion criteria, encompassing 289,839 participants (including 147,632 patients with AA).

The analysis suggested  data indicated NLR was consistently elevated in patients with AA compared with controls, suggesting a reproducible association with systemic inflammation. PLR was elevated in three studies and demonstrated a correlation with disease severity in those analyses. SII and monocyte-to-lymphocyte ratio (MLR) were each evaluated in single studies and were also increased in AA populations. Limited data restricted broader interpretation.

Other indices, including mean platelet volume (MPV) and red cell distribution width (RDW), yielded inconsistent findings. Notably, one study reported that NLR, PLR, eosinophil-to-lymphocyte ratio (ELR), and eosinophil-to-monocyte ratio (EMR) were elevated 12 to 18 months prior to AA diagnosis, indicating a potential temporal relationship between systemic inflammation and disease onset.

“ NLR emerges as a consistent and accessible marker of systemic inflammation in AA, reinforcing AA’s systemic nature,” the authors wrote. “PLR may also correlate with severity, while evidence for other markers remains limited or inconsistent. Early elevations preceding diagnosis suggest a temporal association that warrants prospective validation to determine clinical utility.”¹

Source: de Oliveira LML, Beatriz Ximenes Mendes BX,  Defante MLR, Kreuz M, de Oliveira Rosa L, Kalil L, Bunick C. Complete Blood Count–Derived Indices in Alopecia Areata: A Systematic Review of Inflammatory Markers. Poster 75253. Presented at: American Academy of Dermatology Annual Meeting; March 27-31, 2026; Denver.