The disease is usually immune-mediated in dogs, but may also be caused by trauma, cataracts, infectious canine hepatitis, leptospirosis, ehrlichiosis, or systemic fungal infections.

• 该疾病通常是免疫介导的，但也能由创伤、白内障、传染性犬肝炎、钩端螺旋体病、埃立克体病或系统性真菌感染所引起。