| Criteria | Specifics | Needed for the diagnosis |
| Major criteria | Urticaria for more than six months | The patient must have both major criteria. |
| Hypocomplementemia | ||
| Minor criteria | Venulitis of the dermis (established via biopsy) | The patient must have at least two of the minor criteria. |
| Arthralgia or arthritis | ||
| Mild glomerulonephritis | ||
| Uveitis or episcleritis | ||
| Recurrent abdominal pain | ||
| Positive C1q precipitin test by immunodiffusion with an associated suppressed C1q level |
