Some cases of psoriatic arthritis (PsA) cannot be explicitly diagnosed, especially when the skin and nail lesions present years after the joint disease or are absent. Autoimmunity may also play a role in the development of Dupuytren's disease. However, the simultaneous presence of PsA and Dupuytren's disease is very rare. We present a patient displaying arthritis in multiple small joints, with bone erosions and bony fusions in all four extremities, combined with Dupuytren's disease. Because of the atypical clinical manifestation, the diagnosis perplexed doctors for decades. Without formal treatment, the disease followed a natural course over time. Reviewing the patient's data, a potential diagnosis of PsA, combined with Dupuytren's disease, was eventually made. After surgery, contractures of palmar and plantar fascia as well the thumb web were released, and the hallux valgus was corrected.