A Rare Case of Herpes Zoster Ophthalmicus Secondary to Methotrexate Induced Immunosuppression.

ABSTRACT

Herpes zoster ophthalmicus (HZO) is defined as herpes zoster (HZ) due to involvement of the ophthalmic division of the fifth cranial nerve.1 It is the second most common type of herpes zoster, after thoracic zoster. Herpes zoster affects about 20% of the world's population at least once in their lifetime, with nearly 20% of these showing an ophthalmic involvement.2 It is estimated that 1 million adults in the USA are afflicted with herpes zoster every year. The risk of developing herpes zoster increases considerably with age, reaching 50% in those aged 85 or older. Advanced age and dysfunctional cell-mediated immune responses are two well-established risk factors for varicella zoster virus reactivation. Other risk factors, such as female gender, Caucasian ethnicity, diabetes mellitus, psychological stress, mechanical trauma, heavy metal exposure, as well as family history, have also been postulated. It causes debilitating pain, neuropathy and inflammatory complications.3