Nail Psoriasis: Diagnosis, Assessment, Treatment Options, and Unmet Clinical Needs

Objective. An estimated 40-50% of patients with psoriasis (PsO) have psoriatic nail disease, which is associated with and directly contributes to a greater clinical burden and worse quality of life in these patients. In this review, we examine how recent advances in the use of new diagnostic techniques have led to unproved understanding of the link between nail and musculoskeletal manifestations of psoriatic disease (PsD; e.g., enthesitis, arthritis) and we review targeted therapies for nail PsO (NP). Methods. We performed a literature search to identify which systemic therapies approved for the treatment of PsO and/or psoriatic arthritis (PsA) have been evaluated for the treatment of NP, either as a primary or secondary outcome. A total of 1546 articles were identified on February 18, 2019, and evaluated for relevance. Results. We included findings from 66 articles on systemic therapies for the treatment of NP in PsD. With several scoring systems available for the evaluation of psoriatic nail disease, including varied subtypes and application of the Nail Psoriasis Area Severity Index, there was a high level of methodological heterogeneity across studies. Conclusion. NP is an important predictor of enthesitis, which is associated with the early stages of PsA; therefore, it is important for rheumatologists and dermatologists to accurately diagnose and treat NP to prevent nail damage and potentially delay the onset and progression of joint disease. Further research is needed to address the lack of both standardized NP scoring systems and well-defined treatment guidelines to improve management of PsD.