Disseminated Herpes Zoster Leading to Orbital Apex Syndrome: A Case of MRI-Negative Cranial Neuropathy.

Varicella-zoster virus (VZV) establishes latency in neuronal ganglia following primary infection and can later reactivate as herpes zoster. Disseminated zoster may occur in some cases and is characterized by vesicular lesions appearing beyond the initially affected dermatome. When the ophthalmic branch of the trigeminal nerve is involved, herpes zoster ophthalmicus can develop and may lead to a range of ocular complications. Neurological sequelae are less common, and orbital apex syndrome represents a rare but potentially severe manifestation. This syndrome involves dysfunction of the optic nerve and adjacent cranial nerves within the optic canal and superior orbital fissure, with possible vision loss and ophthalmoplegia. We describe a case of disseminated VZV infection complicated by orbital apex syndrome with cranial nerve III palsy in an immunosuppressed patient, illustrating the diagnostic challenges encountered when clinical findings evolve before confirmatory imaging.