Introduction. Psoriasis is a chronic multi-system inflammatory skin disease with a strong genetic predisposition and autoimmune pathogenic traits, with a worldwide prevalence of 1– 3%. Beyond the physical dimensions of disease, psoriasis has an extensive emotional and psychosocial effect on patients, affecting social functioning and interpersonal relationships (Kim WB1,Jerome D,Yeung J.,2017), mostly affecting the skin, its skin appendages and joints. Nail involvement is an extremely common feature of psoriasis, affecting 10–90% of adult patients with plaque psoriasis, and has been reported in 63–83% of patients with psoriatic arthritis (An Bras Dermatol.,2015). There have been reported twice as many patients with nail involvement suffering from psoriatic artropathy. Because the Psoriasis Area and Severity Index (PASI) does not consider the severity of nail disease, a scale that assesses the extent of involvement of psoriatic nails is needed. A new grading system, the Nail Psoriasis Severity Index (NAPSI) has been proposed. Aim of the study. To provide clinicians with an up-to-date and practical overview of the diagnosis and management of nail psoriasis and with a Nail Psoriasis diagnosis tool Materials and methods. Fingernails of 11 patients with PsA were photographed and scored. Clinical data were collected. Each nail was divided into four quadrants and any nail plate (pitting, leukonychia, red spots on lunula, crumbling) and nail matrix alterations (onycholysis, splinter hemorrhages, subungual hyperkeratosis, oil stains) found were accounted for according to the following: 0 = none, 1 = presence in one quadrant, 2 = presence in two quadrants, 3 = presence in three quadrants, 4 = presence in all quadrants, generating a score that varies from 1-80 for fingernails. A median score has been calculated. Results. Nail psoriasis mostly affects men, is more likely to be associated with severe skin psoriasis and is strongly associated with psoriatic arthritis, affecting almost 100% of Psoriasis patients. Conclusions. The method was easy for assessment and of prompt execution while potentially bringing information about changes in nail plate and matrix, that can be further correlated with cutaneous and articular manifestation.