Red, hot, and painful breast inflammation can have a large number of causes. The history of the condition and clinical observations usually give a pointer to the aetiological diagnosis, which is based on the classic triad of clinical, radiological and histopathological examinations, and guide the choice of additional investigations for rapid therapeutic management of this breast emergency. In breastfeeding women, the cause is often mastitis or, more rarely, an abscess; in non-breastfeeding women, the problem may be mastitis or a periareolar abscess, inflammatory lesions sometimes with secondary infection, or more rarely a real abscess, regardless of a catalogue of various causes. In all cases, the possibility must be considered of inflammatory breast cancer.