A 63-year-old woman with a history of previous anaphylactic reaction to iodate contrast presented with sudden back pain during exertion associated with elevated D-dimer levels. Transthoracic echocardiogram was unremarkable. She was unable to perform a computerized tomography for further evaluation of the aorta due to her allergic background. Transesophageal echocardiogram disclosed a type B aortic dissection. This case report recalls the importance of transesophageal echocardiography in the algorithm for diagnosing aortic dissection in scenarios where CT is not possible.