Which of the following best describes mastitis?

Mastitis is best described as an infection of the mammary gland. This condition typically occurs during breastfeeding when bacteria enter the breast tissue, often through a cracked or sore nipple. The bacteria cause inflammation, leading to symptoms such as redness, swelling, heat, and pain in the affected breast, along with possible systemic symptoms like fever and malaise. Mastitis can disrupt breastfeeding and may require treatment with antibiotics to clear the infection and alleviate symptoms.

The other options refer to different conditions that do not accurately describe mastitis. An infection of the uterus pertains to conditions like endometritis, vascular changes in the nipple may be related to other problems like duct ectasia or other vascular issues, and excessive breast engorgement describes a state of fullness and discomfort in the breasts that may occur when milk is not adequately removed but is distinct from an infection.