eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2015-04-23 3 5 144 145 10.12691/ajmcr-3-5-7 AJMCR2015357 article Racosta Juan Manuel 1 McEwan Lynn 1 Kremenchutzky Marcelo Carlos 1 Morrow Sarah Anne sarah.morrow@lhsc.on.ca 1 University of Western Ontario, London, Ontario Fingolimod is an oral disease-modifying therapy for relapsing multiple sclerosis widely used in Canada as a second-line therapy. Fingolimod increases the risk of infections given its dose-dependent reduction of peripheral lymphocytes, due to the reversible sequestration in lymphoid tissues. We present a case of disseminated facial Herpes Simplex Virus type I infection in a patient using fingolimod, with an atypical distribution of the eruption, likely due to the concomitant exposure to sunlight and application of sunscreen. This case report provides insight about a novel mechanism of disseminationof Herpes Simplex Virus type I, which generally enters damaged epithelium or mucosal surfaces secondary to abrasions or trauma. Since Herpes Simplex Virus type I infection tends to disseminate and is accompanied by visceral involvement in immunosuppressed patients, close surveillance of viral infections and the prompt administration of full-dose antiviral therapy in this population is advised. http://pubs.sciepub.com/ajmcr/3/5/7/ajmcr-3-5-7.pdf multiple sclerosis fingolimod; herpes simplex infection adverse effect