Table 1.

Potential etiology based on retinal arteriole- or venule-predominance of retinal vasculitis.

Primarily retinal arteritis	Primarily retinal phlebitis	Arteritis and phlebitis
Systemic lupus erythematosus	Sarcoidosis	Relapsing polychondritis*
Polyarteritis nodosa	Multiple sclerosis	GPA *
Syphilis	Pars planitis	Crohn’s disease/UC*
Toxoplasmosis	Behçet’s disease	Frosted branch angiitis
HSV/VZV	Birdshot chorioretinopathy	Tuberculosis
IRVAN	HIV associated retinal vasculitis
Churg-Strauss syndrome*	Eales disease
Susac syndrome

HSV: herpes simplex virus; VZV: varicella zoster virus; IRVAN: idiopathic retinal vasculitis, aneurysms, and neuroretinitis; HIV: human immunodeficiency virus; GPA: granulomatosis with polyangiitis; UC: ulcerative colitis.

^*These diseases are rare causes of retinal vasculitis so characterization is based on a small number of descriptions.