Background: Treatments for multiple sclerosis (MS) relapse include intravenous corticosteroids and repository corticotropin injection. Despite available treatment, in the Multiple Sclerosis in America 2017 survey, only 47% of patients reported always/often contacting their MS health care provider (HCP) during relapse. In this study, the Multiple Sclerosis in America 2017 survey participants who received intravenous corticosteroids or repository corticotropin injection for treatment of past relapses completed a follow-up survey to understand how patients characterize relapse severity and to explore predictors of patients contacting their HCP during a relapse. Methods: Patients were18 years and older, diagnosed as having MS by an HCP, and currently using disease-modifying therapy. Patients completed an online survey assessing relapse characteristics and interactions with the HCP treating the patient’s MS. Regression analysis identified predictors of patients contacting their HCP during relapse. Results: Mean age of the 126 respondents was 49.2 years, 81.0% were female, and most (80.2%) had one or more relapses in the past 2 years. Patients estimated that 38.3% of their relapses were mild; 45.1%, moderate; and 16.6%, severe. Number and frequency of symptoms increased with relapse severity. Less than half (46.0%) reported they were extremely likely to contact their HCP during a relapse. The best predictors of being likely to contact the HCP during relapse were the HCP having previously discussed the importance of immediately communicating a relapse and patients’ willingness to accept the HCP’s recommendation for relapse treatment. Conclusions: Findings highlight the importance of HCPs’ advance discussions with patients with MS regarding relapse management to increase the likelihood patients will contact their HCP during relapse.