Introduction: Lewis–Sumner syndrome (LSS) is a demyelinating peripheral neuropathy described in 1982. Methods: We reviewed the charts of nine LSS patients in neurological care for their symptoms, response to different treatment regimens, and pattern of nerve involvement. Results: One patient had an Adie’s pupil. Every patient studied had median nerve involvement. Seven of nine patients required intravenous immunoglobulin (IVIg) therapy and all showed improvement with IVIg. Four of nine patients received oral steroid therapy and had some improvement. Two of nine patients received azathioprine to little effect. Two of nine patients experienced significant trauma while receiving neurological follow-up and their symptoms worsened to a clinically significant degree afterward. Discussion: We noticed a possible association between trauma and symptom severity in cases of LSS with preexisting neurological follow-up. We hypothesize that physical trauma exacerbates LSS. To our knowledge, this is an unreported phenomenon.