Abstract: Objective: To summarize the clinical characteristics and severity factors of nail damage in patients with moderate to severe plaque psoriasis, as well as its impact on quality of life and mental health. Methods: The demographic information, disease characteristics, quality of life, and mental health status of patients with moderate to severe plaque psoriasis who visited the dermatology outpatient clinic from June 2024 to November 2024 were collected through questionnaire survey and scale assessment (including DLQI, NPQ10, and HADS). Patients were divided into two groups based on the severity of nail involvement (NAPSI score): mild (0 ＜ NAPSI ≤ 40) and severe (NAPSI ＞ 40). Differences and correlations between the two groups were analyzed. Results: Among the 177 psoriasis patients, 119 exhibited nail involvement including onycholysis in 95 cases, onychodystrophy in 84 cases, brittle nails in 71 cases. Compared with the mild nail patients in 54 cases, the patients with severe nail (65 cases) had significantly higher incidence rates of head skin lesions and arthralgia, a greater number of nail involvements, longer duration of nail involvement, higher PASI scores, higher NPQ10 scores, and higher proportions of anxiety and depression, with all differences being statistically significant (PS＜0.05). The presence of arthralgia (OR=3.86, 95% CI 1.41-10.55), presence of head skin involvement (OR=6.3, 95% CI 1.74 - 22.84), and a duration of nail involvement exceeding 10 years (OR=11.93,95% CI 2.53-56.16) were all positively correlated with severe nail , (PS＜0.05). Conclusion: The onychia separation is the most common of nail damage in the patients with moderate to severe plaque psoriasis. The severity of nail damage is closely associated with head involvement, arthralgia, PASI score, and duration of nail involvement, which significantly impacts the quality of life and mental health of patients.

Key words: nail psoriasis, severity of nail impairment, quality of life, anxiety, depression