 The history should be explored for the presence of the diseases associated with episcleritis, and the symptoms they cause, such as rash, arthritis, venereal disease, and recent viral infection.Episcleritis may be differentiated from scleritis by using phenylephrine or neosynephrine eye drops, which causes blanching of the blood vessels in episcleritis, but not in scleritis.A blue color to the sclera suggests scleritis, rather than episcleritis.