A nurse is caring for a client who is postpartum and is breastfeeding her infant. Which of the following findings indicates mastitis?

Choice A rationale Mastitis is an inflammatory condition of the breast, often infectious, characterized by localized, unilateral symptoms. A red and painful area in one breast is the hallmark presentation, often accompanied by systemic symptoms such as fever, chills, and malaise. The inflammation is typically caused by bacteria, like Staphylococcus aureus, entering the breast through a cracked nipple and multiplying in the milk ducts, leading to cellulitis. Choice B rationale Cracked and bleeding nipples are frequently the entry point for bacteria causing mastitis, but they primarily indicate nipple trauma, which is a risk factor, not the definitive finding for mastitis itself. This trauma is often due to an incorrect latch or poor breastfeeding technique and generally causes localized pain but not the systemic infection signs characteristic of mastitis. Choice C rationale Swelling in both breasts (bilateral engorgement) is a common, non-infectious condition that occurs when the breasts become overly full of milk, often 3 to 5 days postpartum, or when feedings are missed. This swelling is diffuse, generally relieved by feeding, and does not typically present with the localized erythema, tenderness, and systemic symptoms that are pathognomonic of true mastitis. Choice D rationale An increase in breast milk production is generally a normal physiological process that occurs over the first few weeks postpartum as the supply adapts to the infant's demand. Mastitis, being an infection and inflammation, is more likely to cause a temporary decrease in milk volume from the affected breast due to local tissue swelling and pain, not an increase.