# Co-Occurrence of Psoriasis/Psoriatic Arthritis and Antiphospholipid Syndrome: A Series of Nine Patients from a Single Centre and Literature Review

## TL;DR

This study reports nine patients with both psoriasis/psoriatic arthritis and antiphospholipid syndrome, highlighting their co-occurrence and clinical features.

## Contribution

The novelty lies in identifying a rare co-occurrence of PsO/PsA and APS in a single-center cohort and suggesting a potential shared pathogenic mechanism.

## Key findings

- Nine patients had concurrent psoriasis/psoriatic arthritis and antiphospholipid syndrome.
- APS was the first manifestation in two patients, while seven had PsO/PsA first.
- Six patients tested positive for Lupus Anticoagulant, and anti-cardiolipin antibodies were common.

## Abstract

Antiphospholipid syndrome (APS) is associated with pathogenic antiphospholipid antibodies that lead to repeated arterial and venous thromboses and obstetric complications. Psoriatic Arthritis (PsA) is an inflammatory disease characterised by musculoskeletal inflammation and psoriasis (PsO). Evidence for their co-occurrence is scarce. Nine patients with concurrent PsO/PsA and APS, from the APS cohort of the Department of Pathophysiology of LAIKO Hospital of Athens, were identified. APS was the first manifestation in two patients, while seven had PsO/PsA prior to developing APS. Three patients experienced peripheral arthritis, while four showed axial involvement. Regarding APS events, four patients experienced venous thrombosis, five had arterial thrombosis, and three had simultaneous venous and arterial thrombosis. Six patients consistently tested positive for Lupus Anticoagulant, while anti-cardiolipin IgG/IgM antibodies were our cases’ second most common antiphospholipid antibodies. Further research is warranted to determine whether the IL-23/IL-17 axis is a common denominator in the pathogenesis of both diseases.