Rationale:Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production, complement activation, and deposition of immune complexes in tissues and organs. SLE can involve any region of the visual system. Although ocular manifestations are not part of the classification criteria for SLE, they can be observed in up to one-third of the patients with SLE. They are rarely reported at the time of disease onset. Retinal vasculitis is usually associated with active generalized disease. Due to its low frequency, we report a case of acute necrotizing retinal vasculitis as onset of SLE.Patient concerns and diagnosis:A 25-year-old white female was referred to the rheumatology clinic with gradually and rapid deterioration of the vision due to abnormal vessel permeability in the right fundus with edema along the vessels, occlusion of arterial branches in the middle periphery with leakage of the dye in these areas and indentical but less prominent changes with cotton wool spots in the papillomacular area and extensive hemorrhages in the left eye. The onset of malar rash, arthralgias and positive antinuclear, anti-double stranded DNA, anti-ribosomal P and anti-β2 glycoprotein I antibodies with decreased C4 complement levels, as well as the positive lupus-band test confirmed the diagnosis of SLE.Interventions:Aggressive immunomodulating therapy with high-dose methylprednisolone, intravenous immunoglobulin, and cyclophosphamide was used for suppression of the disease activity followed by azathioprine as maintaince therapy.Outcomes:Substantial improvement and partial resorption of the vasculitic changes, including central retinal artery and vein, was achieved prominently in the left eye. The study was conducted in accordance with the Declaration of Helsinki and written informed consent was obtained from the patient. Because of this, there is no need to conduct special ethic review and the ethical approval is not necessary.Lessons:Inclusion of ocular manifestations among the classification criteria for SLE would enable earlier establishment of the diagnosis and therapeutic interventions in some instances of SLE.