PSORIATIC ARTHRITIS

This is a seronegative inflammatory arthritis

It is found in patterns with psoriasis, a past or family history of psoriasis, or with characteristic changes in the nails (nail pitting).

Sometimes there is a single patch of psoriasis typically hidden in the scalp, gluteal cleft or
umbilicus.

• Arthritis develops in about 7% of patients with psoriasis.

The onset is usually between the age of 25-40 years.

Clinical features

Arthritis involves distal interphalangeal joints usually associated with nail changes.

Extra-articular features

• Skin lesions: scaling lesions typically over extensor surfaces.

• Nail changes: pitting, onycholysis, and horizontal ridging.

Investigations

• RA factor and ANA are negative.

• ESR is moderately raised.

• X-ray shows asymmetrical disease involving distal interphalangeal joints. There is relatively little periarticular osteopenia (that is common in RA).

Management

• NSAIDs

. Methotrexate may be used

• Splints and prolonged rest are avoided because of the increased tendency to fibrous and bony ankylosis.

• Intra-articular injections may be used in persistently active and symptomatic joints.