Herpes Zoster Reactivation in Patients on Methotrexate: An Important Consideration

Abstract

Rheumatoid arthritis frequently necessitates treatment with Disease Modifying Anti-Rheumatic Drugs (DMARDs). Methotrexate (MTX), a commonly prescribed DMARD, has known immunosuppressive properties along with various side effects. We report a case of an adult with rheumatoid arthritis on MTX, who experienced herpes zoster reactivation due to MTX’s immunosuppressive properties. Furthermore, we emphasize the importance of Shingles vaccination in patients on MTX and thorough examination to prevent delayed diagnosis. We describe the case of a 76-year-old male with a history of rheumatoid arthritis who presented to multiple healthcare settings with constant chest pain with radiation to the left shoulder and upper back. Laboratory results and imaging ruled out potential cardiac and pulmonary etiologies of pain. On presentation to his rheumatologist, examination revealed a truncal polyphasic rash, affecting multiple dermatomes. After complete examination, the chest pain was attributed to postherpetic neuralgia secondary to herpes zoster reactivation, and treatment consisted of Gabapentin. Postherpetic neuralgia improved within two weeks, however, the rash persisted. This report presents a rare case of herpes zoster reactivation secondary to MTX immunosuppression. This case report aims to emphasize the importance of increased monitoring and thorough examination in patients treated with immunosuppressive agents and administration of Shingrix vaccine prior to initiating immunosuppressive therapy.