What polyarticular diseases occasionally present with a monoarticular onset
| Rheumatoid arthritis | Reactive arthritis |
| Juvenile idiopathic arthritis | Psoriatic arthritis |
| Viral arthritis | Enteropathic arthritis |
| Sarcoid arthritis | Whipple’s disease |

| Rheumatoid arthritis | Reactive arthritis |
| Juvenile idiopathic arthritis | Psoriatic arthritis |
| Viral arthritis | Enteropathic arthritis |
| Sarcoid arthritis | Whipple’s disease |