Research Article Nail Involvement in Patients with Psoriatic Arthritis in Northern Iran O. Zargari, 1 E. Kazemnezhad Leyli, 2 and S. Z. Azimi 3 1 Department of Dermatology, Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2 Department of Biostatistics, Guilan University of Medical Sciences, Rasht, Iran 3 Department of Dermatology, Skin Research Center, Guilan University of Medical Sciences, Rasht, Iran Correspondence should be addressed to S. Z. Azimi; sz.azimi@yahoo.com Received 31 May 2018; Revised 9 September 2018; Accepted 26 September 2018; Published 15 October 2018 Academic Editor: Ricard Cervera Copyright © 2018 O. Zargari et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Psoriatic arthritis (PsA) results in an increased burden of psoriasis and impairs both quality of life and an individual’s functional capacity. e relationship between nail involvement and PsA in psoriasis is not fully characterized. Aim. To evaluate the frequency and characteristics of nail involvement in psoriatic patients and to assess the relationship with joint involvement. Methods. A total of 197 patients with moderate-to-severe psoriasis were consecutively invited to participate in this cross-sectional study. e patients are divided into two groups: those with and those without psoriatic arthritis. Results. 69.5% of psoriatic (137 out of 197) patients had nail involvement. e most common nail abnormality was onycholysis, followed by pitting and oil droplet changes. Nail involvement was more common in patients with psoriatic arthritis (82.1% versus 57.8%, p=0.001). Conclusion. Nail involvement is commonly associated with PsA. Onycholysis, splinter hemorrhage, and oil drop were significantly more common in the PsA group as opposed to patients with just skin findings. In general, psoriatic patients with arthritis had more severe disease. 1. Introduction Psoriasis is a chronic inflammatory disease affecting up to 3% of the general population. It has a substantial negative impact on health-related quality of life (HRQOL), especially when it involves visible areas of the body such as the face, hands, and nails [1]. Psoriatic arthritis (PsA) has been defined as inflammatory arthritis, usually seronegative, associated with psoriasis [1]. e exact prevalence of PsA is unknown but up to 30% of patients with psoriasis develop psoriatic arthritis [2, 3]. A substantial number of psoriatic patients have nail involvement, varying from 10% to 80%, with an estimated lifetime incidence of 80–90% [4–6]. Nail involvement may be considered an indicator for patients at risk for future psoriatic joint damage [7, 8]; however, this relationship has not been proven [9]. e aim of this study was to assess the overall prevalence of nail involvement in patients with moderate-to-severe psoriasis and to achieve more details on the possible relationship between nail psoriasis and PsA. 2. Materials and Methods 2.1. Patients. is cross-sectional study was conducted from January 2017 to December 2017. During this period, all eligible patients with moderate-to-severe psoriasis who attended to our psoriasis clinic and were candidates for systemic therapy were enrolled in the study. Moderate-to-severe psoriasis was defined as body surface area (BSA) >10% or psori- asis area and severity index (PASI) >10 [10]. e study was approved by the Shahid Beheshti institutional board committee. Informed consent was obtained from each sub- ject. A detailed history was recorded for all subjects, including gender, age, age at the time of onset of the disease, phenotype of psoriasis, disease duration, extent, and severity of the disease. We diagnosed psoriasis according to the clinical findings, and if necessary, a skin biopsy was performed. All patients underwent dermatological examination by a derma- tologist (O.Z.). e following nail changes were recorded: pitting, crumbling, onycholysis, oil drop, subungual hyper- keratosis, and splinter hemorrhage. Hindawi Autoimmune Diseases Volume 2018, Article ID 4608490, 6 pages https://doi.org/10.1155/2018/4608490