Nasal Cytology was performed by scraping the middle part of the inferior turbinate. For the sampling we used a sterile disposable curette (Nasal scraping®, Ep Medica (RA), Italy). The sample was immediately smeared on a glass slide, air dried and then stained with May–Grunwald–Giemsa preparation. The following reading by an optical microscope Nikon E600 (Nikon, Ontario, Canada) allowed us to identify the presence of inflammatory cells (neutrophils, eosinophils, lymphocytes and mast cells) in nasal mucosa. We analyzed a minimum of 50 microscopic fields at x 1000 in oil immersion and the count of each cell type was expressed by a semi-quantitative grading (from 0 to 4 (link)) (13 (link),14 (link)). During the nasal cytological examination at T0, the clinical-cytologic grading was also calculated for each patient. Since CRswNP is a pathology with an elevated risk of relapse and poor control despite conventional therapy, negative prognostic factors responsible of relapses and lack of symptoms control were identified (15 (link)). Many studies demonstrated that allergy, asthma, and acetylsalicylate (ASA) sensitivity are determining factor for negative outcomes. The correlation between these clinical parameters and nasal cytology results (nasal eosinophilia, neutrophilia, mastocytosis) led to the development of a score, called clinical-cytologic grading (CCG), whose value defines the relapse prognostic index, classified in low, intermediate, or high (Table 1) (16 (link)).