Concurrent Presentation of Pustular Psoriasis and Late-Onset Rheumatoid Arthritis: A Diagnostic Challenge in a Community Hospital Setting

The coexistence of autoimmune diseases presents a significant diagnostic challenge in clinical practice, particularly in settings with limited resources. This case report details a rare instance of pustular psoriasis occurring concurrently with rheumatoid arthritis, underscoring the complexities involved in diagnosing overlapping autoimmune disorders. A 70-year-old male with a history of chronic heart failure, atrial fibrillation, and other comorbidities presented to a rural community hospital with a year-long persistent rash and joint and back pain. Physical examination and blood tests revealed high inflammatory markers. A dermatological assessment, including a skin biopsy, diagnosed generalized pustular psoriasis. However, the atypical presentation of acute polyarthritis led to further investigations, revealing elevated rheumatoid factor and anti-citrullinated protein antibody levels, resulting in a diagnosis of late-onset rheumatoid arthritis. The patient underwent a comprehensive treatment regime, including prednisolone, cefazolin, oral terbinafine, methotrexate, and infliximab, leading to gradual symptom improvement to the previous activity of daily life and discharge on the 27th day of hospitalization. This case illustrates the diagnostic intricacies in identifying concurrent autoimmune disorders and highlights the crucial role of general physicians in systematically approaching complex cases in resource-limited settings. It emphasizes the need for heightened clinical vigilance and a multifaceted diagnostic approach when managing patients with overlapping rheumatic symptoms, advocating for consideration of coexisting conditions in autoimmune diseases.