Case Presentation: A 53-year-old female with chronic small fiber polyneuropathy and erythromelalgia presented with severe headaches, nausea, vomiting, diarrhea, body aches, photophobia, and neck stiffness for two days. Symptoms started one week after receiving intravenous immunoglobulin (IVIG) for an erythromelalgia flare. On presentation to the ER, she was afebrile and physical examination was unremarkable. Respiratory [...]