Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX
To differentiate psoriatic arthritis (PsA) from other types of inflammatory arthritis, assess the following clinical features:
- Presence of psoriasis: Current or past psoriasis is a key indicator, as PsA commonly occurs in people with psoriasis or a family history of psoriasis NICE NG65.
- Dactylitis (sausage digits): This is a strong clinical sign with a high likelihood ratio for PsA and spondyloarthritis, and its presence alone justifies referral for specialist assessment NICE CKS,NICE NG65.
- Enthesitis: Inflammation at tendon or ligament insertion sites is common in PsA but should be considered alongside other features, as enthesitis alone has weak predictive value NICE CKS,NICE NG65.
- Peripheral arthritis pattern: PsA often presents with peripheral joint involvement that can be asymmetric and may affect distal interphalangeal joints, unlike rheumatoid arthritis which is typically symmetric NICE CKS,NICE NG65.
- Extra-articular manifestations: Look for associated features such as nail changes (pitting, onycholysis), uveitis, and inflammatory bowel disease, which support a diagnosis of PsA or related spondyloarthritis NICE CKS,NICE NG65.
- Response to NSAIDs: Improvement of symptoms within 48 hours of NSAID use supports inflammatory arthritis but is not specific to PsA NICE NG65.
- Family history: A first-degree relative with psoriasis or spondyloarthritis increases the likelihood of PsA NICE NG65.
Referral to rheumatology is recommended if PsA is suspected, especially with dactylitis or persistent enthesitis, to confirm diagnosis and initiate early treatment to prevent joint damage NICE CKS,NICE CKS.