[Atypical arthritis of the hands : Collagenosis-part 2]

Progressive systemic scleroderma (PSS) and mixed connective tissue disease (MCTD) represent vasculitic autoimmune diseases from the group of collagenoses with manifestations in various organ systems such as the skin, the internal organs and the joints.

To present the atypical arthritis patterns of the hands in PSS and MCTD that differ from those in rheumatoid arthritis (RA) and psoriatic arthritis (PsA) in the context of clinical and serologic findings and in consideration of the classification of PSS and MCTD.

Narrative review based on the current literature on the subject from the radiological and rheumatological point of view.

In PSS, combinations of acral soft tissue atrophy, nonreactive acro-osteolysis, and interstitial calcifications can be visualized by projection radiography, which in the final stage can lead to a scleroderma claw hand. Digital pharmacoangiography of the hands can be used to reliably diagnose manifest vascular occlusions of the digital arteries. MCTD is characterized by various overlapping symptoms of at least two systemic autoimmune diseases and most frequently presents in the hand with symmetrical involvement of the PIP (proximal interphalangeal), MCP (metacarpophalangeal) and wrist joints with the manifestation of so-called "puffy fingers".

The presented morphological atypical arthritis patterns of the hands in PSS and MCTD differ considerably from the typical patterns in the hands in RA and PsA. MRI is useful to diagnose early stages and pharmacoangiography can be used to differentiate between temporary and manifest digital vascular occlusions.