We report a case of reactivated biopsy-proven cytomegalovirus proctitis complicating the course of severe COVID-19 pneumonia treated with dexamethasone, anakinra and lopinavir/ritonavir. No other contributing factor was found than iatrogenic immunosuppression and COVID-19 immune dysregulation. We draw attention to the immunosuppressive risk when treating severe COVID-19 pneumonia with immunomodulators.