Psoriatic arthritis (PsA) belongs to the group of seronegative spodyloarthropathies. Except PsA this group of disorders also contains: ankylosing spondylitis, reactive arthritis, juvenile spondyloarthropathies, arthritis with inflammatory bowel disease and nondifferentiated spondyloarthropathies. The definition “seronegative” is related to the absence of rheumatoid factor (RF) in IgM class. Fast destruction of the joints is typical symptom of PsA (especially in arthritis mutilans). About 1/3 of the patients manifest joint’s symptoms before psoriasis. This article describes 46-year old female patient with seronegative arthritis. Diagnostic difficulties were related to earlier course of the disease. One year before CREST syndrome was diagnosed – based on clinical, laboratory and radiological tests.