skip to main content

Dactylitis Pathology — SCE Rheumatology MCQ

Instant feedback + full explanation. One question, done properly.

EasySpondyloarthropathyDactylitis PathologySCE Rheumatology

A 48-year-old woman with psoriatic arthritis has diffuse swelling of her right index finger, consistent with dactylitis. Which pathological process best explains the sausage-shaped appearance of the digit?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Combined flexor tenosynovitis, synovitis and diffuse extrasynovial soft-tissue inflammation

Explanation lettering: B = shown as A · D = shown as B · A = shown as D

Dactylitis is diffuse inflammation of multiple tissue compartments throughout a digit. Imaging typically demonstrates flexor tenosynovitis together with digital-joint synovitis and extrasynovial abnormalities, including subcutaneous oedema and soft-tissue thickening; enthesitis and extensor paratenonitis may also contribute. Their combined distribution produces uniform swelling of the whole finger or toe and hence the term “sausage digit.” Synovitis alone (A), isolated flexor tenosynovitis (B), or subcutaneous oedema alone (D) does not account for the characteristic multi-compartment inflammation. Osteitis or periostitis may be present in some cases, but isolated bone inflammation (E) is not the pathological basis of dactylitis.

Reference: Felbo SK, Østergaard M, Sørensen IJ, Terslev L. Which ultrasound lesions contribute to dactylitis in psoriatic arthritis and their reliability in a clinical setting. Clinical Rheumatology. 2021;40:1061–1067. https://pubmed.ncbi.nlm.nih.gov/33155158/