Systemic inflammatory diseases commonly affect the sclera, cornea, retina, and orbit, and can pose a serious threat to sight. They encompass both primary and secondary vasculitic disorders and specific granulomatous inflammatory conditions. As well as direct eye involvement from the systemic inflammatory process, there can be signs of ocular ischaemia due to carotid or ophthalmic arteritis, hypertensive retinopathy, and ocular complications such as chloroquine maculopathy related to anti-inflammatory drug treatment. Additionally, systemic infection relating to the eye, either as the result of primary infective disease processes or infection secondary to immunosuppression, might be mistaken as endogenous intraocular inflammation. Infection can closely mimic the ocular signs of endogenous inflammation, and in selected patients (such as those who have been immunosuppressed to treat vasculitis and who additionally have had invasive surgery, indwelling intravenous catheters, or systemic sepsis), it might be necessary to specifically exclude infection by the sampling and culturing of intraocular fluids and tissue.