To present a case of orbital inflammation and optic perineuritis preceding vesicular eruption in herpes zoster oph-thalmicus (HZO).

An 84-year-old woman with a history of gall bladder cancer and hypertension complained of left periorbital eryth-ematous edema and discomfort. On examination, visual acuity was 20/25 bilaterally; no tenderness, proptosis or oph-thalmoplegia was observed. Pupils were equal, round, and reactive to light without relative afferent pupillary defects. Slit-lamp examination revealed severe conjunctival injection and chemosis without keratitis or uveitis. The remainder of the ocular exami-nation was unremarkable. Magnetic resonance imaging confirmed left-sided preseptal swelling with an enlarged left lacrimal gland, high signal intensity of the retrobulbar fat and optic nerve sheath. Systemic antibiotic therapy with steroids was started un-der a presumed diagnosis of idiopathic orbital inflammatory disease, but the clinical presentation was unresolved. After 2 days, vesicular lesions confined to the first division of the trigeminal nerve and pseudodendritic keratitis developed on the left side leading to a diagnosis of HZO. Treatment with acyclovir immediately resolved anterior segment inflammation and periorbital edema. While on therapy, visual acuity deteriorated to 20/125 and the pupil became dilated and unresponsive to light over a few days. All signs and symptoms of acute orbitopathy and postherpetic neuralgia had resolved 3 months later with the exception of pupil abnormality and visual acuity.

HZO may present with symptoms and signs of orbital inflammation and optic perineuritis even in the absence of a vesicular rash. Thus, HZO should be considered in the differential diagnosis of unexplained acute orbital syndromes.