DD arthritis in the ED

HOA hypertrophic osteoarthropathy
PPP syndrome: pancreatitis (+ pancreatic cancer), panniculitis (subcutaneous fat necrosis), polyarthritis with peri-arthritis (often oligoarthritis) due to fat necrosis with high lipase. Eosinophilia possible (Schmid triad in pancreatic cancer: subcutaneous fat necrosis („erythema nodosum-like“), polyarthritis, eosinophilia).

https://www.mdcalc.com/acute-gout-diagnosis-rule