Acute onset of psoriatic spondyloarthritis as a new manifestation of post-streptococcal reactive arthritis: a case series.

Streptococcus is well associated with a myriad of inflammatory diseases. Among others, this bacterium is linked to the triggering of psoriasis and to post-streptococcal reactive arthritis (PSRA), an arthritis which is typically confined to peripheral joints. Three patients who developed acute psoriatic spondyloarthritis (SpA) following a recent streptococcal infection are described in this article. We searched the existing literature for cases of axial involvement in PSRA and reviewed the association between streptococcal infection and psoriasis or psoriatic arthritis )PsA). In all patients, psoriatic SpA occurred within 7-10 days of a confirmed streptococcal infection. The main presenting syndrome was inflammatory back pain with evidence of acute axial spondyloarthritis on magnetic resonance imaging. One patient had guttate psoriasis, the second patient developed pustular psoriasis, and the third patient had exacerbation of pustular palmoplantar psoriasis. Two patients required treatment with tumor necrosis factor alpha (TNF-α) blockers. Axial involvement in PSRA is very rare. A potential association of streptococcal infection and development of PsA has been explored in several articles. However, to the best of our knowledge, acute psoriatic SpA as a manifestation of PSRA has yet to be described. Acute psoriatic SpA should be considered in the differential diagnosis of new-onset inflammatory back pain followed by psoriasis in young adults who had a recent throat infection. KEY POINTS: • Our case series describes three cases of acute psoriatic spondyloarthritis that occurred within 7--10 days of a confirmed streptococcal infection and progressed to full blown chronic disease. • Acute psoriatic spondyloarthritis as a manifestation of post streptococcal reactive arthritis should be considered in the differential diagnosis of new onset inflammatory back pain followed by psoriasis in young adults who had a recent throat infection.