This patient is showing signs of a reaction that is peculiar to vancomycin called red man syndrome. It is an infusion-related reaction and is characterized by the development of a pruritic, erythematous rash. There may be burning and discomfort and more severe symptoms, or it may be so mild that it goes unreported. It is related to the speed of the infusion, so if it occurs, the infusion should be stopped until symptoms abate. Antihistamines, such as oral diphenhydramine, have a sedating and antipruritic effect and are the recommended treatment for red man syndrome. Topical hydrocortisone cream has an anti-inflammatory and immunosuppressive effect on the rash of red man syndrome. Systemic corticosteroids are also a recommended treatment for more severe or refractory cases. However, these therapies are only symptomatic treatments and are not as effective as stopping the infusion. Importantly, the infusion can be resumed at a slower rate once symptoms resolve.