A Pilot Study of Warm and Cold Compress to Reduce Injection Site Erythema Due to Peginterferon-beta-1a in MS

Inclusion Criteria: * Diagnosis of MS made at least 3 months prior based on McDonald criteria. * Age 18 or more * Ongoing treatment with PEG for 30 days or more at screening * No MS exacerbation for 60 days prior to screening. * Score of ≥50 on screening ISR Erythema Index * Home access to microwave oven and freezer * Written informed consent Exclusion Criteria: * Any contraindication to warm or cold compress: * Inability to sense temperature change by patient report * Metal implant near injection site (e.g. injection near intra-abdominal baclofen pump) * History of allergy or intolerance to local heat or cold application * Bleeding disorder * Concomitant use of any topical prescription medication at injection site * Females who are breast-feeding, pregnant or have potential to become pregnant during the course of the study (fertile and unwilling/unable to use effective contraceptive measures) * Cognitive deficits that would interfere with the subject's ability to give informed consent or perform study testing. * Any other serious and/or unstable medical condition