Inflammation of the breast (mastitis) with or without infection or redness has a variety of etiologies and presentations that range from the fairly benign blocked duct to the more serious breast abscess. True infectious mastitis can present in a manner that is easily identifiable, or it can present in a subtle and ambiguous fashion. Some women are challenged with recurrent mastitis, and often the underlying etiology is never discovered. This review will assist the clinician in recognizing, efficiently diagnosing, and effectively treating breast inflammation caused by infectious and noninfectious processes, including recurrent mastitis. Tables and a flowchart that outline breast inflammation and recurrent mastitis are provided.