Interferon beta as an enhancer of paraviral exanthema during influenza virus infection

We herein describe the case of a 33-year-old male patient who presented at our emergency department with concomitant flu symptoms and a maculopapular rash. The evening prior to consultation he had first noticed erythematous macules on the trunk and arms, which had then rapidly progressed overnight. The rash was markedly pronounced at injection sites of interferon-beta (IFN-β) administered for relapsing remitting multiple sclerosis (RRMS) (see Fig. 1a). Pruritus was moderate (3/10 numeric rating scale). Fever up to 38°C, fatigue, hoarseness and muscle and joint pain had begun four days prior to consultation. Another four days earlier, the patient and his family had visited a private party. Some of the guests as well as the patient's wife and children experienced equivalent flu symptoms albeit no skin eruptions.

Keywords: COVID-19; antiviral response; influenza; interferon-beta; paraviral exanthema.