Matteo Gelardi
Nasal cytology provides a direct and minimally invasive assessment of the cellular environment of the nasal mucosa and may represent a valuable tool within the emerging framework of precision rhinology. Beyond its traditional diagnostic role, cytological examination can identify distinct local inflammatory patterns characterized by neutrophils, eosinophils, mast cells, and mixed cellular profiles, thereby revealing biological heterogeneity that may not be fully captured by clinical phenotype or systemic biomarkers alone. This review discusses the potential role of nasal cytology as a local cellular phenotyping approach in inflammatory diseases of the upper airways. Particular emphasis is placed on the interpretation of major cytological patterns, their relationship with underlying inflammatory mechanisms, and their possible integration with clinical, laboratory, and endoscopic information. The repeatability of nasal sampling also allows for longitudinal evaluation of cellular changes over time, supporting the concept of cytology as a dynamic local biomarker for monitoring disease evolution and treatment response. Nasal cytology has also recently undergone Delphi-based standardization, providing consensus recommendations that support methodological consistency, reproducibility, and broader clinical implementation. Representative original micrographs from a long-standing educational nasal cytology archive are included to illustrate the principal cellular phenotypes discussed. Although further standardization, validation, and integration with molecular biomarkers are needed, nasal cytology may contribute to a more individualized assessment of nasal inflammatory diseases by providing direct information from the target tissue. Its incorporation into multimodal diagnostic pathways could help bridge traditional rhinological evaluation and personalized management.