Psoriatic arthritis

To evaluate the clinical pattern of psoriatic arthritis in patients attending a tertiary referral centre in South India.

Case records of one hundred and sixteen patients with psoriatic arthritis (PsA) who had attended our Rheumatology Department were analysed using demographic, clinical, laboratory and radiographic variables and the data were compared with other studies.

Among 116 patients, 78 were males and 38 were females (ratio 2:1). Peak incidence (69%) was in the fourth and fifth decades. One patient had juvenile psoriatic arthritis (onset <16 years of age). Symmetric polyarthritis (48.3%) was the commonest subtype. Arthritis followed the skin lesions in 50.8% of patients, preceded in 12.1% and occurred simultaneously in 37.1%. Knee (66.4%) was the commonest joint involved. Extra-articular features like sausage digits (19%), enthesitis (7.8%) and eye manifestations (1.7%) like conjunctivitis and uveitis were observed. Psoriasis vulgaris (81%) was the commonest psoriatic lesion. Scalp (57.8%) was the most common hidden site. All the three patients with DIP arthritis alone had nail lesions. ESR and C-reactive protein were elevated in 51.7% and 43.9% of patients respectively. Rheumatoid factor was positive in 3.4 % and antinuclear antibody (ANA) was present in 5.4% (3/56) of patients. HIV infection was detected in 2.3% (1/44) of patients. Radiographic features like sacroiliitis (11.2%), calcaneal spur (7.8%), erosions (5.2%) and syndesmophytes (5.2%) were observed. One patient had 'pencil-in-cup deformity'.

Psoriatic arthritis is more common in males. Symmetric polyarthritis is the commonest subtype. Arthritis commonly follows the skin lesions. Psoriasis vulgaris is the most common skin lesion and scalp is the commonest hidden site. ESR and CRP can be normal in psoriatic arthritis.