 Periorbital cellulitis must be differentiated from orbital cellulitis, which is an emergency and requires intravenous (IV) antibiotics.In contrast to orbital cellulitis, patients with periorbital cellulitis do not have bulging of the eye (proptosis), limited eye movement (ophthalmoplegia), pain on eye movement, or loss of vision.If any of these features is present, one must assume that the patient has orbital cellulitis and begin treatment with IV antibiotics.