Which ultrasound lesions contribute to dactylitis in psoriatic arthritis and their reliability in a clinical setting.

Dactylitis in PsA appears to encompass several lesions, most often subcutaneous changes combined with synovitis and/or flexor tenosynovitis. Reliability of scoring established ultrasound lesions of dactylitis in a clinical setting is moderate-excellent. Key Points • Dactylitis in psoriatic arthritis consists of multiple ultrasound lesions • A dactylitis ultrasound sum-score gives an impression of severity by including all lesions • Reliability of ultrasound scoring of dactylitis components is good.