Three rings vulvoscopy (TRIV) has previously been described to facilitate the diagnosis and treatment of vulvar discomfort. The distinction between outer, middle, and inner vulvar rings is based on differences in anatomy, histology, and embryology. The vulvoscopy index was designed considering the patient's history, clinical exam, and assessment of the specificity and localization of the lesion relative to the vulvar ring. This paper evaluated the sensitivity, specificity, and diagnostic accuracy of the vulvoscopy index in detecting vulvar dermatosis compared with histopathology as a reference test. Structured ISSVD vulvodynia pattern questionnaire and TRIV form data were utilized for the study. The data obtained were analyzed using StatSoft (Dell, Austin, Texas), Statistica 12 (TIBCO®, Palo Alto, CA), and SPSS 20 (IBM, Armonk, NY). Ethical approval for the study was obtained from the Institutional Review Board of Polyclinic Harni, and all patients provided written informed consent. The histopathological diagnosis of vulvar dermatosis was confirmed in 72 patients at first biopsy. Lesions specific for vulvar dermatosis were visible by TRIV in 82 patients. The resulting difference of ten patients were participants with early vulvar dermatosis. In six of them, vulvar dermatosis was confirmed at a later biopsy during the study period. There was no statistically significant difference between the scores of points (median and range), frequency and relative frequency of vulvar findings within one item of the vulvoscopy index and histopathology, except for ten patients with early forms of vulvar dermatoses. The sensitivity, specificity, and diagnostic accuracy of the vulvoscopy index for detecting vulvar dermatosis were 100%, 96.1%, and 96.9%, respectively. The positive and negative predictive values were 0.88 and 1.00, respectively. The vulvoscopy index represents a compelling clinical test for detecting vulvar dermatoses. Differences between vulvoscopic and histopathological diagnostics implicate the impossibility of histopathology in recognizing early forms of vulvar dermatoses. Accordingly, early dermatoses could represent a key area for applying this test. ClinicalTrials.gov Identifier: NCT02732145.