Acute mastitis is an acute purulent infection of the mammary gland, commonly occurring in women during the postpartum breastfeeding period, especially more frequently seen in primiparous women. It usually occurs within three months after delivery, particularly in the third and fourth weeks postpartum. Therefore, it can also be referred to as postpartum mastitis or lactational mastitis. The main causes are due to bacterial invasion, stagnation of milk, and a decrease in the body's immune function. The primary pathogens are generally Staphylococcus aureus, with occasional cases involving Streptococcus. In such instances, it is recommended to conduct a routine blood test for the mammary gland and an ultrasound to determine the severity of the mastitis.