BACKGROUND: Nail involvement has a tremendous impact on psoriasis patients. Early detection and prompt intervention of psoriatic nail damage are necessary.
METHODS: A total of 4290 patients confirmed to have psoriasis between June 2020 and September 2021 were recruited from the Follow-up Study of Psoriasis database. Among them, 3920 patients were selected and divided into the nail involvement group (n = 929) and the non-nail involvement group (n = 2991) by inclusion and exclusion criteria. Univariate and multivariable logistic regression analyses were performed to identify the predictors of nail involvement for the nomogram. Calibration plots, the receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were used to evaluate the discriminative and calibrating ability and clinical utility of the nomogram.
RESULTS: Sex, age at onset, duration, smoking, drug allergy history, comorbidity, sub-type of psoriasis, scalp involvement, palmoplantar involvement, genital involvement, and PASI score were selected to establish the nomogram for nail involvement. AUROC (0.745; 95% CI: 0.725-0.765) indicated the satisfactory discriminative ability of the nomogram. The calibration curve showed favorable consistency, and the DCA showed the good clinical utility of the nomogram.
CONCLUSIONS: A predictive nomogram with good clinical utility was developed to assist clinicians in evaluating the risk of nail involvement in psoriasis patients.

Shifts in skin microbiome are considered to be involved in the pathogenesis of psoriasis. However, data on the microbial dysbiosis of nail psoriasis are scarce. In this study, we aim to investigate and characterize the nail bacterial and fungal microbiome in patients with psoriasis. Nail samples were collected prospectively from 36 subjects with nail psoriasis, 24 psoriatic subjects without nail involvement and 32 healthy controls. Amplicon sequencing was performed to evaluate the bacterial and fungal community compositions. Significant alterations in the bacterial microbiome were found in the nail samples of psoriatic patients. The unaffected nails in psoriatic patients were associated with higher bacterial diversity, and a higher relative abundance of Enhydrobacter, whereas nail psoriasis was correlated with a decreased relative abundance of Anaerococcus. Shifts in fungal community composition were reflected by a higher proportion of Malassezia in the unaffected nails of psoriatic patients and an increased proportion of Candida in psoriatic nails. Shifts in the nail microbiome in psoriasis suggest a potential role of microbes in the development of nail psoriasis. Future researches focusing on these microorganisms may help to explain the pathogenesis of psoriasis.

Nail psoriasis is a refractory disease that affects 50-79% skin psoriasis patients and up to 80% of patients with psoriatic arthritis (PsA). The pathogenesis of nail psoriasis is still not fully illuminated, although some peculiar inflammatory cytokines and chemokines seems to be the same as described in psoriatic skin lesions. Psoriatic nail involving matrix can cause pitting, leukonychia, red spots in lunula, and nail plate crumbling, while nail bed involvement can result in onycholysis, oil-drop discoloration, nail bed hyperkeratosis, and splinter hemorrhages. The common assessment methods of evaluating nail psoriasis includes Nail Psoriasis Severity Index (NAPSI), Nail Assessment in Psoriasis and Psoriatic Arthritis (NAPPA), Nail Psoriasis Quality of life 10 (NPQ10), and so on. Treatment of nail psoriasis should be individualized according to the number of involving nail, the affected site of nail and presence of skin and/or joint involvement. Generally, topical therapies are used for mild nail psoriasis, while biologic agents such as etanercept are considered for severe nail disease and refractory nail psoriasis. Even though the current literature has shown some support for the pathogenesis, clinical presentation, or therapies of nail psoriasis, systemic review of this multifaceted disease is still rare to date. We elaborate recent developments in nail psoriasis epidemiology, pathogenesis, anatomy, clinical manifestation, diagnosis, differential diagnosis, and therapies to raise better awareness of the complexity of nail psoriasis and the need for early diagnosis or intervention.

Dermoscopy is an efficient and non-invasive technique which has been widely used in the diagnosis of nail disorders including nail psoriasis (NP). Many nail dermoscopic features are considered as clues to NP. The aim of this study was to investigate specific dermoscopic features of fingernail psoriasis and the correlation between the severity of nail lesions or systemic inflammation, and psoriasis severity of skin and nail. This observational study recruited 135 patients with fingernail psoriasis (1186 fingernails) and 30 patients with onychomycosis (80 fingernails). All of the involved fingernails were examined with a handheld dermatoscope. The Nail Psoriasis Severity Index score (NAPSI) score, Psoriasis Area and Severity Index (PASI) score, body surface area (BSA), and detailed history of patients with psoriasis were recorded. Mann-Whitney U-test, χ2 -test, Spearman\'s correlation, and Kruskal-Wallis H-test were used for statistical analysis, and the significance threshold was p < 0.05. The trial registration number was 2020-SR-045. We identified onycholysis as the most common feature (93.3%) of fingernail psoriasis. Red lunula, longitudinal fissures, transverse grooves, nail plate crumbling, trachyonychia, oil-dropping sign, erythematous border of an onycholytic area, subungual hyperkeratosis, and dilated streaky capillaries were relevant to NP severity (p < 0.05). Red lunula, transverse grooves, nail plate crumbling, trachyonychia, oil-dropping sign, erythematous border of an onycholytic area, splinter hemorrhages, and dilated streaky capillaries were relevant to systemic inflammation severity (p < 0.05). The total NAPSI score was positively associated with the PASI score and BSA (p < 0.0001). The thumb had a higher NAPSI score than the other fingers (p < 0.05). In conclusion, dermoscopic features can improve the accuracy of diagnosis of nail psoriasis, and have correlations with psoriasis severity.

BACKGROUND: Various systemic immunomodulating therapies have been investigated to treat nail psoriasis, but the efficacy remains unclear.
OBJECTIVE: To perform a systematic review and network meta-analysis to evaluate the efficacy of small molecule inhibitors and biologics in treating nail psoriasis.
METHODS: Eligible studies in online databases were identified until March 10, 2020. To assess the efficacy of small molecule inhibitors and biologics, network meta-analyses with surface under the cumulative ranking curve of improvement in nail score at 10 to 16 and at 24 to 26 weeks, as well as 100% improvement of Nail Psoriasis Severity Index (NAPSI), were performed.
RESULTS: Thirty-nine studies with a total of 13 treatment arms involving 15,673 patients with nail psoriasis were included. An network meta-analysis showed that tofacitinib (weighted mean difference, 56.67; 95% confidence interval [CI], 35.87-77.48) and ixekizumab (weighted mean difference, 59.40; 95% CI, 45.87-72.93) presented the most improvement of nail score at 10 to 16 weeks and 24 to 26 weeks, respectively. For 100% improvement of the Nail Psoriasis Severity Index, ixekizumab showed the best efficacy among all treatments (odds ratio, 2.98; 95% CI, 1.74-5.10).
CONCLUSIONS: Insufficiency of eligible data and no long-term follow-up data.
CONCLUSIONS: Tofacitinib and ixekizumab presented the best efficacy for treating nail psoriasis in 10 to 16 weeks and 24 to 26 weeks, respectively.

BACKGROUND: Nail involvement is common in psoriasis patients, however, there are few detailed studies of clinical parameters related to disease severity and therapeutic efficacy.
OBJECTIVE: Our retrospective study aimed to describe the prevalence and clinical characteristics in nail psoriasis patients and determine possible associations between multiple clinical parameters and disease severity or therapeutic efficacy.
METHODS: A total of 89 nail psoriasis patients were included and investigated using dermoscopy. The Nail Psoriasis Severity Index (NAPSI) and the Nijmegen-Nail Psoriasis Activity Index tool (N-NAIL) were used to measure the severity and improvement of nail psoriasis. Severity and efficacy-related parameters were also analysed.
RESULTS: Subungual hyperkeratosis (94.4%) was the most commonly observed nail feature. Coexistence of pitting and leukonychia, transverse grooves and thickening were more commonly observed in juveniles than adults. Patients with more severe nail psoriasis were more likely to have more nails affected and develop discolouration. The efficacy of treatment after fixed intervals of treatment was analysed. Most clinical parameters were not related to therapeutic efficacy, including disease duration, age at onset and number of nail signs. However, after six months of treatment, the presence of transverse grooves was shown to be associated with better efficacy. Based on comparison of NAPSI and N-NAIL scores relative to the first visit, the presence of transverse grooves, longitudinal ridges or discolouration were associated with better efficacy.
CONCLUSIONS: Clinicians should be aware of the clinical parameters related to severity and the use of therapeutic efficacy in choosing individualized treatment and predicting prognosis.