Frequent causes
| Causes | Number (%) |
|---|---|
| Infection | 28 (23.1) |
| Infectious endocarditis | 4 |
| HIV/AIDS | 4 |
| Tuberculosis | 3 |
| Other | 17 |
| NIID | 37 (30.6) |
| Polymyalgia rheumatica | 9 |
| Still's disease | 7 |
| Sarcoidosis | 3 |
| ANCA-associated vasculitis | 3 |
| Rheumatoid arthritis | 3 |
| Other | 12 |
| Malignancy | 13 (10.7) |
| Malignant lymphoma | 8 |
| Castleman's disease | 2 |
| Other | 3 |
| Other | 15 (12.4) |
| Drug fever | 3 |
| Fraudulent fever | 3 |
| Other | 9 |
| Unknown | 28 (23.1) |
ANCA, anti-neutrophil cytoplasmic antibody; NIID, non-infectious inflammatory disease;.