Peripheral joint involvement is a common, potentially debilitating feature of psoriatic arthritis (PsA). Joint involvement is commonly symmetrical and polyarticular similar to rheumatoid arthritis (RA) but it can also be oligoarticular, asymmetrical or occasionally monoarticular. Involvement of the distal interphalangeal joints is a feature which distinguishes PsA from RA. Articular involvement in PsA can be severe with a mutilating arthropathy found in about 5%. These patients are characterised clinically by digital shortening and on radiographs by erosion on both sides of the joint and/or osteolysis. Treatments targeting joint disease frequently reduces symptoms and signs resulting in prevention of damage progression.