Clinical and immunogenetic characteristics of psoriatic arthritis: a single-center experience from South India

AimThe aim of this study was to determine the clinical characteristics and prevalence of HLA B27 in patients with psoriatic arthritis presenting to a tertiary care centre in South India. BackgroundAlthough the prevalence of psoriasis is high in India, there is paucity of data, especially on Ps A. Materials and methodsThis retrospective study included 141 patients satisfying the ClASsification criteria for Ps A (CASPAR). Demographic, clinical, and laboratory data of the patients were collected through personal interviews, clinical examination, appropriate investigations, and analysis of case records. HLA-B27 typing by PCR method was done for all patients. ResultsAmong the 141 patients, 89 subjects were males and 52 were females, and the male to female ratio was 1.7:1. Polyarthritis (n=51, 36.2%) was the most common Ps A subtype noted during the study, followed by oligoarthritis (n=48, 34%), spondyloarthropathy (n=29, 20.6%), distal interphalangeal (DIP) predominant arthritis (n=25, 7.8%), and arthritis mutilans (n=2, 1.4%). Arthritis preceded skin involvement in 9.2% (n=13) of the cases. Dactylitis was seen in 24.1% (n=34) of the patients. Extra-articular features like enthesitis (n=16, 11.3%) and eye involvement (n=1, 0.7%) were also observed. Deformities were seen in 32.6% (n=46) of the subjects. The most common type of psoriatic skin lesion noted was psoriasis vulgaris (n=119, 84.4%). Nail involvement was seen in 17.7% (n=25) of the patients and it was observed in all subjects with DIP predominant arthritis (100%). Family history of psoriasis was present in 11.3% (n=16) of the patients. The number of patients positive for HLA B27 was 16 (11.3%). Additionally, the antigen positivity was noted in 35.7% (n=10) of the patients with spondyloarthropathy. ConclusionPs A was more common in males. Polyarthritis and oligoarthritis were the most prevalent subtypes. The prevalence of HLA-B27 in our study population was 11.3% and was found to be strongly associated with spondyloarthropathy.