Psoriatic arthritis mutilans is a rare but aggressive type of advanced joint disease in patients with psoriasis. It represents a diagnostic challenge, given the heterogeneity of the manifestations at the beginning of the disease. The present article describes a case of a woman with undiagnosed psoriatic arthritis mutilans . Patient case A 67-year-old woman presented to a rheumatologist with complaints of pain in her lower back.

Furthermore, she was experiencing morning stiffness lasting for 2 hours and gradually affecting the knees, ankles, elbows, shoulders, and wrists followed by small joints. She had a 15-year history of pain in multiple joints and a symmetric and migratory arthritis. She reported lesions on her nails for more than 10 years. She was previously diagnosed with rheumatoid arthritis and was treated with non-steroidal anti-inflammatory drugs (NSAIDs), hydroxychloroquine,…