Vaginal Herpes Zoster While Under Treatment for Relapsing-Remitting Multiple Sclerosis With Diroximel Fumarate

Multiple sclerosis (MS) is an autoimmune demyelinating disorder that disproportionately affects middle-aged women, and is capable of resulting in severe disability. However, the use of disease-modifying therapies has profoundly contributed to the improvement in the morbidity of the disorder. Diroximel fumarate (DRF) is a second-generation drug that has seen success in the treatment of relapsing-remitting MS (RRMS). While its relatively mild side effects of gastrointestinal discomfort are known, the less common complications are often missed in clinical settings. This includes a resulting susceptibility to opportunistic infections. In this case report, we describe a patient who experienced lymphopenia, recurrent yeast infections, and labial shingles while on the medication. This case highlights the side effects and the rare complications of the immunomodulator, DRF.