Single Center, Open Label, Study of Preparation H on Erythema in Relapsing MS Patients Treated With PLEGRIDY

Inclusion Criteria: * A confirmed diagnosis of relapsing multiple sclerosis, as defined by McDonald criteria. * Age 18 to 70 years old, inclusive, at the time of informed consent. * Naïve to PLEGRIDY or less than or equal to 12 months on PLEGRIDY therapy. Exclusion Criteria: * Primary progressive, secondary progressive or progressive relapsing MS. * Concurrent enrollment in any clinical trial of an investigational product. * Known allergy to any interferon or any component of PLEGRIDY (peginterferon beta-1a). * Known allergy to phenylephrine, pramoxane or any component of Preparation H. * History of hypersensitivity or intolerance to naproxen or acetaminophen (Tylenol) that would preclude the use of at least 1 of these during the study. * History of inadequate response to subcutaneous interferon beta therapy. * History of human immunodeficiency virus, hepatitis C virus antibody or current hepatitis B infection. * History of premalignant and malignant disease including solid tumors and hematologic malignancies (except basal cell and squamous cell carcinomas of the skin that have been completely excised and are considered cured). * History of any clinically significant cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, and renal, or other major disease, as determined by the Investigator. * History of seizure disorder or unexplained blackouts. * History of suicidal ideation or an episode of clinically severe depression (as determined by the Investigator) within 3 months prior to Day 1. * Serious local infection (e.g., cellulitis, abscess) or systemic infection (e.g., pneumonia, septicemia), at the discretion of the Investigator, within 3 months prior to Day 1. * History of drug or alcohol abuse (as defined by the Investigator) within 6 months prior to Day. * Active bacterial or viral infection. * Inability to comply with study requirements.