Background  Behçet’s disease (BD) and psoriasis are chronic inflammatory diseases characterized by multisystemic vasculitis and epidermal hyperplasia respectively. Although it has been found that the pathogenesis of BD and psoriasis share common perspectives, reports of patients who have both diseases in concurrence are rare.

Objectives  To analyse and evaluate the clinical manifestations of BD patients who have psoriasis together.

Methods  Retrospective evaluation of the medical records of nine BD patients who were also diagnosed with psoriasis at the BD Specialty Clinic of Severance Hospital was carried out. We analysed the characteristics of patients and the clinical activity of both diseases, and also the effect of the treatment of one disease against the other.

Results  Of the nine BD patients who also had psoriasis, male to female ratio was 1 : 2. Two (22.2%) patients had a complete type of BD and seven (77.8%) patients had an incomplete type of BD. For the psoriatic lesions, all nine (100%) patients were diagnosed as psoriasis vulgaris. Five (55.6%) patients had BD as the preceding disease and four (44.4%) patients had psoriasis as the preceding. All five patients who formerly developed BD followed by psoriasis had an active state of BD, but the activity of psoriasis of all nine patients was minimal to average.

Conclusion  In this study, we evaluated the clinical manifestations of nine patients who had BD and psoriasis together. Although the exact pathogenesis remains unclear, there might be some influence by each disease to the other between BD and psoriasis.